NIDA Resource Center for Health Services Research

DRUG ABUSE PREVENTION NEEDS ASSESSMENT METHODOLOGIES
A Review of the Literature
August, 1997

Barry S. Brown, Ph.D.
University of North Carolina at Wilmington

Definition and Application to Drug Abuse Prevention Programming
Needs Assessment Data Collection Strategies: TABLE 1
Structure of Paper
Needs Assessment Strategies: Surveys
Needs Assessment Strategies: Problem-Oriented Measures of Drug Use
Needs Assessment Strategies: Ethnographic Measures
Assessing Community Resources to Provide Prevention Services
Conclusions
References

Definition and Application to Drug Abuse Prevention Programming

    Needs assessment is used to understand the nature and extent of a health or social problem in a community with the intent to respond appropriately to that problem. The findings from a needs assessment are used to make program, policy, and/or budget decisions. Needs assessment strategies are research based to permit planning, programming, and resource expenditure guided by data rather than subjective judgments or political considerations.

    This report focuses on community-based needs assessment strategies for drug abuse prevention. Therefore, the strategies described are those that have been developed to clarify the direction and the urgency of drug abuse prevention both nationally and within communities. Many, if not most, of the techniques employed have relevance for treatment needs assessment as well.

    Specific to drug abuse prevention, needs assessment strategies typically are concerned with understanding the extent to which drug use is being initiated within a community, the types of drugs used, the characteristics of new users, and the extent and nature of continuing drug use in the community. A significant concern is whether existing prevention programs are targeting appropriate groups with relevant messages.

    Specific questions for needs assessment regarding prevention may include the following: What is the incidence of drug use in the community? What is the pattern of drug taking within the community in terms of drugs used, characteristics of drug users, and the progression in drug taking among users? What are the attitudes and behavioral intentions of individuals regarding drug use?

    Because needs assessment is designed to meet a community’s concerns regarding prevention efforts, the community should be involved in setting study parameters. The involvement of community members in formulating questions to be explored can forestall any risk that community interests and concerns are poorly addressed. Indeed, the involvement of individuals responsible for authorizing a community needs assessment in planning and conducting the study not only prevent later misunderstanding, but also encourages cooperation from all segments of the community in conducting the assessment and increases the likelihood of the ultimate utility of the findings (Boyer & Langbein, 1991).

    The prevention issue addressed has implications for the assessment strategy employed. Where the prevention issue involves understanding and containing the initiation of drug use, the assessment strategy may best involve a community survey employing probability sampling with particular attention to monitoring the incidence as well as prevalence of drug use. Where the prevention concern also involves understanding and containing community problems associated with drug use, the assessment strategy may best involve nonprobability sampling surveys conducted in health care, social service, and criminal justice agencies in which the consequences of drug use are reflected.

    Conducting a needs assessment carries with it the implication that the needs identified will be addressed through increased or modified prevention programming. To identify problems in the absence of intent or capacity to resolve those problems can only be demoralizing to the community. Responding to a community’s identified needs will result in a commitment of people, time, and dollars. The individuals responsible for addressing identified needs should be known, and either the resources for responding to identified needs or a plan for acquiring those resources should be available.

    Needs assessments must be conducted in a timely manner. The problem being addressed is usually one of some urgency. Therefore, the community is likely to assume that the information received will result in a course of action. The needs assessment should be conducted with the sense of urgency felt by the community, balanced by concerns about the rigor of the study and the accuracy of its findings.

    Finally, the needs assessment should be replicated in succeeding time periods to determine the extent to which policies and programs initiated are effective in reducing the problems identified. Repeated needs assessments can reveal the changing nature of community needs, for example, by identifying changes in reported access and acceptability and/or use of a drug by a defined population. Current information regarding availability of drugs, acceptance of drug taking, and the characteristics of drug users is important to any prevention activity.

Overview and Conceptual Framework

    Needs assessment describes the numbers and characteristics of the population needing prevention services (i.e., immediately seeking or requiring services). Needs assessment is a critical aspect of community prevention planning, clarifying the needs of community residents and permitting informed decision making regarding the allotment of resources in meeting those needs. The term need in this context refers to the capability of deriving benefit from prevention services. A distinction between demand and need can be made in association with the urgency with which those services are required. Although that distinction is most often applied to treatment, the same distinction may have relevance for prevention in terms of individuals whose characteristics, behaviors, and/or circumstances place them at particular risk for drug use (demand) and their age-group peers at lower levels of risk for drug use (need).

    Thus, although all members of certain age groups (e.g., preadolescents and adolescents) may be at some level of risk for initiating drug use, a hierarchy of need for prevention services may be created such that individuals are characterized as being more or less vulnerable based on the presence of risk or protective factors. A combination of individual and community characteristics may suggest that some individuals demonstrate demand for prevention services based on heightened vulnerability, whereas other individuals, at lower levels of vulnerability, but at a susceptible age, are viewed as needing prevention services.

    As depicted in Table 1, and as described below, the data-gathering strategies for achieving estimates of the need and demand for prevention services involve a mix of direct measures (i.e., population surveys employing probability sampling), indirect measures (i.e., assessments based on the impact of drug use and drug users on health, social service, and criminal justice systems), and ethnographic study (i.e., information based on observation and/or description derived from individuals experiencing the problem being addressed).

    The data resources listed in Table 1 typically are used to characterize drug use at a point in time and to monitor trends in drug use over time. Increasingly, there has been an interest in developing statistical models to provide estimates of the drug-using population for purposes of permitting still more precise understanding of the impact of drug use on community service systems and better informing the community’s response to drug use.

    Although needs assessment involves estimating the size and clarifying the nature of drug- using and risk populations, a second area involves the nature and extent of services required to respond to the need or demand identified. To determine the size and character of that response calls for a description of the size and character of the population to be served, but it also calls for a description of services available in the community. This suggests an assessment of the nature and quantity of prevention services currently being provided and the extent to which available services are and are not being accessed and, where essential services are not being accessed, the impediments to their use. The interest and capacity of the community to provide prevention resources also need to be assessed.

Structure of Paper

    The primary focus of this paper is a review of the strategies used to conduct drug abuse prevention needs assessment in the community. The strategies described are largely from the field of epidemiology and include survey techniques, field studies, and ethnographic investigation. The paper explores the strengths and weaknesses of each strategy, cost issues, and implementation. Estimation models, which make use of data gathered through these strategies, are described.

    Needs assessment strategies vary in their validity and in the expense associated with conducting them. Therefore, communities may need to make difficult choices between elaborate, rigorous, and expensive data-gathering strategies and approaches that are more restricted in their coverage. Although the latter are more likely to raise questions regarding credibility, they may prove more manageable in terms of cost. In all situations, but particularly in those using less rigorous techniques, it is important that investigators interpret their data with caution and not overinterpret their findings. On the other hand, findings from limited, carefully conducted investigations can provide important information about drug abuse problems and prevention programming needs in a community. Most communities will need to purchase the best needs assessment available to them under limited budgets. Therefore, any discussion of needs assessment must address issues of cost and benefit associated with the range of strategies available.

    Another important facet to assessing community needs is understanding resources available to address those needs. Consequently, the paper explores strategies to assess current and potential community resources to address the identified prevention programming needs.

    Finally, the paper examines strategies for communicating needs assessment findings to community members to promote their use in establishing or augmenting prevention services. If the needs assessment report is to be useful, its communication to the community must be carefully planned and implemented.

Needs Assessment Strategies: Surveys

Household Surveys Employing Probability Sampling

    For both prevention and treatment planning, general population surveys are widely regarded as "among the most common and reliable methods of obtaining useable data for a needs assessment" (United Way of America, 1982). The population survey employing probability sampling permits the selection of subjects who can be seen as statistically representative of the study population. Thus, probability sampling permits every individual in the targeted population to be available to the survey, thereby allowing the unbiased selection of individuals and the unbiased canvasing of needs. If the interview or questionnaire used to assess needs is found to measure needs consistently over periods during which no change would be expected (i.e., is reliable) and accurately reflects the behaviors or attitudes of respondents (i.e., is valid), the resulting survey can provide a powerful tool for needs assessment. Indeed, population surveys employing probability sampling have been the foundation of national needs assessment efforts.

    The National Household Survey on Drug Abuse (NHS), conducted initially under sponsorship by the National Institute on Drug Abuse (NIDA) and later by the Substance Abuse and Mental Health Services Administration (SAMHSA), has been employed since 1974 to monitor drug use trends. The NHS is stratified (e.g., for age and ethnicity), employs area probability sampling of persons aged 12 and older living in U.S. households, and oversamples individuals between the ages of 18 and 34 (Turner, Lessler, & Gfroerer, 1992). The data collection strategy involves the use of a structured, closed-ended, face-to-face interview in which the respondent is guaranteed confidentiality and anonymity. Self-administered answer sheets are completed by the respondent for several sensitive questions (NIDA, 1991a; SAMHSA, 1995).

    The Epidemiological Catchment Area (ECA) study also was influential. The ECA sampled respondents in five communities between 1980 and 1984 to determine rates of depressive disorders, anxiety disorders, drug abuse/dependence, and alcohol abuse/dependence in the general population. The ECA used face-to-face interviews and employed DSM-III criteria to define respondent status. The study revealed unexpectedly high rates of psychological disorder in the general population and underscored the importance of the relationship between substance abuse/dependence and psychological disorders (Regier et al., 1988).

    Assuming measures are valid and reliable, well-conducted probability surveys of the population at risk afford the clearest guarantee of obtaining samples that accurately reflect the larger population. In sampling from households, the potential exists for making the target population virtually everyone with stable residence in the community or, in the case of the NHS, virtually everyone with stable residence in the country. The disadvantages of probability sampling relate primarily, but not exclusively, to cost. The use of a household survey can have limitations beyond cost for understanding prevention need. In that regard, the respondents reached through a household survey constitute a comparatively stable portion of the population and thereby are likely to provide an incomplete picture of prevention need. That is, those in need of drug abuse prevention efforts will live both within and outside of stable households (e.g., college dormitories) and, therefore, will be only partly represented in a survey restricted to households. Moreover, one can assume that the more likely that a drug is associated with a particular subgroup (e.g., "ecstasy" with college students) or lies outside mainstream experience (e.g., heroin), the less likely it is to be reported by respondents in a household survey. Nonetheless, understanding the rates of use and the characteristics of the users of those drugs is significant to prevention planning. Thus, in assessing prevention need, surveys of households need to be augmented by studies of selected risk populations. Indeed, in 1991 the sampling frame for the NHS was broadened to include homeless shelters, military bases (civilians only), college dorms, and other nonhousehold settings

    Household and school-based surveys are particularly important to the development or modification of prevention programming in a community. Because these surveys capture both the incidence and prevalence of drug problems, they can be employed to clarify emerging drugs of concern as well as reporting drugs that are in significant use in a community (i.e., these surveys are useful in assessing both prevention demand and prevention need). With prevention programming, there is often a particular concern with adolescent and young adult populations (as suggested by the use of school surveys), since these groups are viewed as particularly vulnerable to the initiation or escalation of drug use. Escalation may involve increases in frequency of drug use and/or involvement in a broader range of substances. If the community is focused on understanding prevention programming needs, it may be useful to oversample adolescent and young adult populations to obtain an understanding of substance-using behaviors in those age groups. Panel studies could help clarify changing substance use patterns in those groups. Attitudes and beliefs regarding substances and substance use in preadolescent, adolescent, and young adult populations also may be assessed.

    In addition to the necessity of sampling all relevant parts of the population, there is a need to determine that the instruments and procedures used to gather data guard against error. As described by Gfroerer, Gustin, and Turner (1992), two kinds of error are a particular concern with assessments of drug use prevention need. On the one hand, the respondent may make cognitive errors reflecting lack of understanding or capacity to follow the interview or questionnaire and/or deficiencies in memory. On the other, the respondent may be inclined to give socially desirable responses to questions designed to tap sensitive areas of behavior. A variety of strategies have been developed to reduce ambiguity and misunderstanding of interview or questionnaire items and to enhance recall. Self-administered answer sheets and guarantees of confidentiality and anonymity have been used to reduce the risk of respondents giving socially desirable responses. Finally, completed surveys are subject to quality-control procedures to ensure that client responses are consistent across items addressing comparable behaviors and issues.

Surveys of Targeted Populations

    Surveys have been conducted of population subgroups that are of particular interest to prevention programming. These groups, which include various subpopulations of adolescents and young adults (e.g., school dropouts, runaway youth, juvenile offenders, college students, enlisted military), have been targeted because they are vulnerable to initiating or escalating drug use and because they risk being understudied in household surveys. The surveys have used probability-sampling strategies for high school and military populations, and nonprobability sampling for other populations whose numbers and characteristics are unknown, making probability sampling impossible.

    The Monitoring the Future study, or the National High School Senior Survey as it is frequently known, has been conducted annually since 1974 under NIDA sponsorship by the University of Michigan’s Institute for Social Research. The study currently surveys high school graduates, college students, and eighth and tenth grade students in addition to high school seniors. The Monitoring the Future study involves stratification (by size, geographic region, urbanicity, etc.) of schools and a multistage process to obtain a probability sample of high school students. In addition, beginning in 1976, panel studies have been conducted annually with a random sample of each graduating class. Thus, data are available on drug use and attitudes for a consistent sample of respondents. Written questionnaires, rather than face-to-face interviews, are administered as a part of routine school activity (Johnston, O'Malley, & Bachman, 1989, 1995). Like the NHS, the Monitoring the Future study affords an opportunity to monitor trends in drug use for an identified population over an extended period. Whereas the identified population for the NHS includes all those living in households, the identified population for the Monitoring the Future study are the members of a restricted age group.

    Student populations are of special concern to prevention programming and, therefore, have received particular attention. Not only the federal government, but various state and local jurisdictions as well, have developed their own school-based survey strategies. Indeed, the State of Maryland has been conducting school surveys virtually as long as the Monitoring the Future study has been in existence (Maryland State Department of Education, 1994). As with household surveys, the risk in relying on student surveys to understand adolescent drug use lies in acting as if adolescents attending school are representative of all adolescents. Thus, in understanding the prevention needs of a community, it is important to sample the less visible populations of school dropouts, runaway youth, and juvenile offenders. Information regarding the substance-using behaviors and attitudes of those populations may provide a needed corrective to the data available from school attendees. Surveys or other strategies may be called upon to clarify the functioning of those populations.

    In addition to student populations, surveys have been undertaken of military personnel (Bray et al., 1983, 1986; Burt & Biegel, 1980) and of offenders incarcerated in state facilities (Innes, 1988).

Surveys Using Nonprobability Sampling

    Surveys of populations less accessible than households, high school students, armed forces personnel, or prisoners used nonprobability sampling strategies. The populations studied—runaway youth, school dropouts, and juvenile justice clients—are each important to understanding a community’s prevention needs and may each demand differing prevention strategies.

    These surveys require (a) a definition of the targeted population; (b) a sampling strategy that guards against bias in the selection of respondents; and (c) the use of an instrument that guards against error in self-reported behaviors and other areas of inquiry. In terms of study design, the sample drawn needs to meet criteria that accurately describe the population of concern. For example, describing runaway youth requires a definition of some minimal period of time of absence from the parental or foster home. The definition will set the parameters for the population and allow the cautious generalization of findings.

    The size and characteristics of these populations are not sufficiently well known to permit probability sampling; consequently, the investigator needs to ensure that the sample drawn reflects the population in question adequately and contains no known biases. Thus, a sample of runaway youth would not be drawn solely from a shelter population, but would include the streets, soup kitchens, and so on. Ideally, respondents would be obtained from these different settings in proportion to the use made of them by runaway adolescents. An additional strategy employed in nonprobability surveys has been targeted sampling (Watters & Biernacki, 1989) in which the investigators assess the characteristics of the population being sampled and correct the sample as it is being drawn to reflect those characteristics. It is also apparent that in nonprobability surveys, it is particularly urgent to keep refusals to be interviewed to a minimum and to avoid biasing the sample in the direction of respondents most likely to volunteer for study (e.g., those most in need of the compensation typically offered to subjects).

    As with probability sampling, it is important to ensure that the measure employed uses a vocabulary and format that the target population understands. Sensitive questions must be addressed in a manner that encourages honest responses. Again, it is crucial to guarantee each respondent's confidentiality and anonymity.

Issues in Survey Methodology

    A number of innovative strategies have been used in conjunction with drug use surveys to reduce inaccuracies associated with cognition and social desirability, and in an effort to reduce cost. Anchoring interviewees' responses to time frames through the recall of personal experience is useful in reducing response error (Hubbard, 1992); that is, individuals volunteer events for specific time frames that can be used to anchor in time their responses regarding drug use or other behaviors.

    Self-administered questionnaires, permitting privacy in responding to sensitive questions, appear to reduce the influence of social desirability on reporting. Turner, Lessler, and Devore (1992) found increased reporting of drug use when respondents were permitted to use self-administered questionnaires than when respondents answered face-to-face queries.

    Concerns about cost have led to experimentation with telephone surveys as an alternative to face-to-face studies. In a review of studies of "private" behaviors including but not restricted to drug use, Gfroerer and Hughes (1992) report that face-to-face interviewing is generally associated with self-reports of greater drug use and of lower income and education. Studies by Aquilino (1992), Aquilino and LoSciuto (1989), and LoSciuto, Aquilino, and Licari (1993) found lower rates of self-reported drug use by African American respondents in telephone as compared to face-to-face interviews. Johnson, Hougland, and Clayton (1989) found lower rates of self-reported drug use for university respondents in telephone as compared to face-to-face interviewing. On the other hand, McAuliffe and his colleagues (1987) have argued that a study of Rhode Island respondents to a telephone drug use survey did not suggest inaccuracy in reporting. Although they acknowledge lower estimates of drug use in the studies initiated to date comparing telephone to face-to-face interviewing, McAuliffe and colleagues (1994) assert that the differences are insignificant in relation to estimates of prevalence, may be nonexistent in relation to rates of heavy use or dependency, and may be further reduced through the refinements to telephone interviewing suggested in their manual.

    State planning offices report applying survey data from national samples to their own local situations (Minugh, n.d.). Through this practice, unwarranted assumptions may be made about the comparability of national to local circumstances. Thus, even if efforts are made to correct for differences in demographic characteristics, differences in community variables (e.g., drug availability, drug potency, police activity, population density) may nonetheless make applying national findings to local conditions inappropriate. Issues in extrapolating from available data sets to local communities are explored further in the section "Strategies for Estimating Drug Use."

Needs Assessment Strategies: Problem-Oriented Measures of Drug Use

    A number of strategies assess the impact of drug use on the health, criminal justice, and social service agencies in a community. These strategies are described as using indicator data or indirect measures (Kimmel, 1992). In these initiatives, as with surveys, effort is made to monitor drug use over time. However, whereas surveys are concerned with obtaining representative or unbiased samples, studies using problem-oriented measures are typically restricted in their capacity to conduct equally rigorous study. Thus, the clients of any one service system may differ in important ways from the clients of another in demographic and background characteristics generally, and in drug use characteristics specifically.

Drug Use Data from the Health Care System

    Drug abuse is a health care issue that both directly and indirectly affects a number of areas of health care delivery. Drug abuse is associated with infectious diseases (e.g., tuberculosis, sexually transmitted diseases [STDs], hepatitis B and C, and acquired immunodeficiency syndrome [AIDS]), with psychological and alcohol problems, and with adverse reactions such as overdoses. Assessing the consequences and concomitants of drug use can help us to understand the populations negatively affected by drug use, to determine the types of drugs responsible for creating specific health care problems in a community (Gfroerer, 1991; Kimmel, 1992), and to provide a basis for monitoring the changing nature of drug use in a community (Gerstein & Harwood, 1990).

    The extent to which drug use is associated with medical emergencies and deaths has been determined by collecting data at hospital emergency rooms and medical examiners' offices. The data collection strategies developed by federal authorities include a nationwide sample of programs chosen from a mix of metropolitan (cities and surrounding areas) and nonmetropolitan areas. In the federally maintained Drug Abuse Warning Network (DAWN), data are collected from more than 500 hospitals (emergency rooms) in 21 metropolitan areas and additional nonmetropolitan areas, and from 135 medical examiners' offices in 27 metropolitan areas and additional nonmetropolitan areas. Brief forms have been developed to record demographic characteristics, drugs used, and routes of drug administration. For emergency room clients, sources of substances, reasons for the use of the substances reported, and reasons for emergency room admission are recorded. For medical examiner cases, cause and manner of death are determined. All emergency room admissions and all medical examiner cases are included, provided they show evidence of either a medically inappropriate use of prescription or over-the-counter drugs or a use of illicit substances. The data are used to characterize metropolitan areas and, through repeated administration, to report trends both locally and nationally (NIDA, 1991b, 1991c).

    The methodology developed to assess and monitor drug use in the health care system on a national level is also available to local jurisdictions. Fewer resources are required than for surveys; however, such an effort requires the commitment of staff to perform data collection and entry and to carry out analysis as well as to conduct quality-control procedures to assure the integrity of data collected. Savings may result from the use of time sampling strategies as long as the times at which data are gathered are chosen without bias.

    Assessment of drug use involving the health care system or other indicator data cannot provide the estimates of incidence and prevalence available through use of population surveys employing probability sampling. Such assessment can, however, clarify selected issues regarding drug use and prevention need in a community. Specifically, we can determine the drugs creating a problem for individuals in a community and the nature of individuals experiencing difficulties in association with the nonmedical use of drugs. Through the regular collection of data, we can establish trends in the nature of drugs abused and the characteristics of abusers. That information then can be used to understand issues to develop or extend the community's prevention efforts.

    Because the data collected are from one segment of the community service delivery system (i.e., from one component of the health care system), they must be interpreted cautiously. That is, the data clarify community drug problems and identify characteristics of drug users affecting a significant, although limited, portion of the community’s service systems. The value of indicator data can be enhanced by collecting additional data from other segments of the community (i.e., regarding other indicators) to clarify the nature of the drug use and to identify characteristics of the drug users seen in other parts of the community’s service systems.

    Within the health care system, data also can be gathered from agencies providing treatment for STDs, hepatitis, tuberculosis, and AIDS. All are diseases of significance to the community, and all are diseases to which drug users are particularly vulnerable. Monitoring clients of these systems can provide significant information about characteristics of drug users at high risk and the association between drug use and infectious disease. In addition, agencies serving pregnant women and infants may provide useful data regarding women in the community.

    Monitoring the mental health and alcoholism treatment systems provides an opportunity to assess drug use and drug users from a population that may differ significantly from those found in facilities treating infectious diseases, since mental health and alcoholism programs are more likely to see noninjection drug users. The issue of psychiatric comorbidity makes it apparent that these populations have, and will continue to have, significance for understanding community drug use and drug users (McLellan, 1991).

    Within the health care system, we should seize the opportunity to study and monitor admissions to drug treatment. Both drugs used and characteristics of users are of concern in developing a picture of drug use in the community and establishing an appropriate prevention response.

Drug Use Data from the Criminal Justice System

    The criminal justice system includes a significant number of drug users. As with entrants into the health care system, strategies have been devised for assessing and monitoring criminal justice clients. The Drug Use Forecasting (DUF) program, initiated in 1988 by the Department of Justice, obtains structured interviews and urine specimens from a sample of adult and juvenile booked arrestees (consecutive admissions) in 24 cities nationwide (not all cities gather data on juveniles). Data are analyzed by demographic characteristics, drugs reported/identified, charges, and so on. (National Institute of Justice [NIJ], 1995). As with DAWN health care settings, using a consistent instrument and uniform sites permits trends in drug use to be monitored over time.

    As with any survey strategy, the accuracy of findings can be compromised by inaccurate self-reports or by refusals to participate. The risk of inaccuracies and refusals would seem to be heightened in working with a criminal justice population—particularly a criminal justice population awaiting adjudication (i.e., a population whose drug use could be used against them). Indeed, studies suggest a significant underreporting of drug use by both adult arrestees (Mieczkowski, Barzelay, Gropper, & Wish, 1991) and juvenile offenders (Feucht, Stephens, & Walker, 1994). It is important to clarify that confidentiality and anonymity will be maintained with all self-report information provided. Biological data also should be gathered when feasible. In fact, the DUF program obtains response rates of greater than 90% of arrestees sampled and obtains urine specimens from more than 80% of those sampled (NIJ, 1995).

    In reporting drug use by arrestees, DUF relies on the results of urine testing, thereby increasing accuracy through the use of a biological measure rather than risking the influence of memory or social desirability on self-report. Urine drug testing identifies recent drug use only, thus risking a conservative—and incomplete—report of arrestees' drug use. Nonetheless, the capacity to understand drug use associated with danger to the health and safety of the community makes DUF reporting a significant contribution to prevention planning. Hair assay may be used to extend the reporting period (Cone, Yousefnejad, Darwin, & Maguire, 1991; DuPont & Baumgartner, 1995; Mieczkowski, Landress, Newel, & Coletti, 1993; Wang, Cone, & Zacny, 1993; Wang, Darwin, & Cone, 1994), although caution has been urged in association with the potential for environmental contamination (Goldberger, Caplan, Maguire, & Cone, 1991; Wang & Cone, 1995).

    In addition to arrestee data, information regarding drug use in a community may be obtained through law enforcement activities involving purchases of street drugs, the interdiction of drugs entering a community, and arrests for drug violations. Drug buys can provide data regarding the types of drugs available on the street as well as their strength and purity, thereby helping to identify drugs having implications for prevention needs. However, it may not be readily apparent whether a given drug buy accurately represents the type and potency of drugs available in a community. Similarly, drugs obtained through interdiction may have high or low claims to being representative of drugs available. In addition, drug arrests require clarification regarding circumstances under which the data have been collected. Arrestee numbers and types may represent normal police activity or may reflect a special concern of the community, such as an effort to "clean up" a particular area, and thereby be atypical of the drug problem in the larger community. Although gathered under far less rigorous conditions than other data described in this section, data from law enforcement can be useful if placed in a context of community events and if used in conjunction with data from other sources.

Drug Use Data from the Social Service System

    Data from social service agencies have been far less frequently employed for needs assessment than have data from health care and criminal justice agencies. Among social service agencies, only shelters for homeless individuals and runaway youth have received significant attention as sites for assessing or serving drug users. Awareness and concern about the numbers of drug users in those facilities have accompanied increasing concerns about both psychiatric comorbidity and HIV infection. Large numbers of homeless individuals show evidence of drug use and psychological dysfunction (Task Force on Homelessness and Severe Mental Illness, 1992), while the runaway population is perceived to be significantly involved in drug use and unprotected sex to obtain drugs and survive on the streets (Pires & Silber, 1991). Surveys of homeless and runaway populations have been undertaken as one-time initiatives to characterize the population in question rather than as part of a monitoring strategy to assess ongoing community need for prevention efforts (e.g., NIDA, 1993, regarding homeless persons; Rotheram-Borus & Koopman, 1991, regarding runaway youth).

    Other social service settings may be significant to understanding numbers and characteristics of drug users as well as the relationship between a selected community concern (e.g., abuse and neglect cases) and substance abuse. However, in association with both the expense and the imposition on individuals and agency staff, those settings should be selected carefully in terms of their significance for drug abuse and the likelihood of locating individuals not found in other settings from which samples are being drawn.

Drug Use Data from the Work Site

    Drug testing in the workplace is now a common practice (DuPont, Griffin, Siskin, Shiraki, & Katze, 1995; Willette, 1986). Urine screens for a range of drugs of concern to employers and to the community provide another data source regarding drug use (American Management Association, 1995). Biological data have the advantage of being viewed as more valid than the self-report data available in other assessments and are collected from a segment of the public that is not otherwise available. Correlating drug use with community problems and negative consequences leads to sampling from populations that survive largely on the fringes of society. The use of data from job applicants provides information on drug use in the community from a population more likely to have a stake in mainstream life. Additional findings may be available from Employee Assistance Programs (EAPs) or from random urine screens of current employees. Data from job applicants and employees, collected over time, provide a significant perspective on drug use in the community. Collecting as many data points as possible enhances an understanding of drug use and the characteristics of drug users in order to plan prevention programming or to modify existing programs.

    Data from employers should be obtained without individual identifiers; that is, the anonymity of individuals is protected. Investigators have a responsibility to individuals and to the community to have procedures in place to guarantee the confidentiality and security of all data collected.

    Teachers and school counselors, probation officers, caseworkers in the social service system, administrators of homeless shelters, police, housing authority personnel, and medical practitioners are community experts in a position to observe and monitor different aspects of the community. They can be viewed as "key informants" regarding various aspects of community functioning (although, as described below, the term key informant is also used to describe those who are more intimately a part of the drug scene). The views of community experts are important, not only because they are uniquely positioned to describe drug use within their areas of responsibility, but also because they can influence community opinion regarding drug use within those areas. The viewpoints of individuals in positions of significant responsibility and authority have the potential to reverberate through the community.

    Two strategies are often employed to gather information. First, individuals can be interviewed using open-ended questions relating to several general themes the interviewer plans to explore, allowing latitude for the interviewer to pursue issues that the key informant may introduce. A second strategy involves the use of focus groups in which community experts meet to discuss issues the group leader poses in an effort to share ideas and observations and to clarify issues. The capacity of community experts to clarify trends in the nature and extent of drug use problems as well as to identify needed community prevention services has significant implications.

Uses of Data from Surveys Employing Probability and Nonprobability Sampling

    Although no data collection strategy is perfect, most researchers would agree that surveys employing probability sampling provide the best estimate of drug use in a community. As discussed above, obtaining accurate findings with that strategy requires that all segments of the population of interest be represented in the sample drawn, and that the instrument used is capable of obtaining unbiased responses (i.e., of minimizing the risk of cognitive errors and of errors associated with social desirability). When properly conducted, surveys using probability sampling provide data that can be used to estimate incidence and prevalence of drug use and consequently are the most useful strategies for determining the prevention needs in a community. Survey strategies using nonprobability sampling explore drug use in relation to problems created by, or in association with, that drug use. These strategies measure drug use by individuals who are already experiencing and creating problems in the community. Consequently, they are generally seen as less well suited to a determination of issues for the prevention of drug use.

Strategies for Estimating Drug Use

    Needs assessment for both prevention and treatment has been concerned with constructing estimation models that can be used to describe the prevalence of drug use in the general population and in selected subpopulations. Thus, the NHS has been used to generate estimates of drug use prevalence through the application of weights for age, sex, and ethnicity to approximate their representation in the general population while compensating for survey nonresponse and undercoverage (NIDA, 1991a, 1991b). In this manner, the number of users of different drugs has been estimated (within certain confidence intervals), and those estimates have been used to understand prevention needs and, at times, to judge the success or failure of national drug abuse strategies.

    In instances in which a particular community is concerned with estimating the rate of drug use but lacks specific data, the community may elect to develop synthetic estimates. As described by Wickens (1993), a calibration population (or populations) for which drug use is known is used to generate information about drug use in the target population for which drug use information is lacking. Synthetic estimates may employ a variable or variables related to drug use, such as rates of drug arrests or of AIDS, which are known for other communities (calibration populations) as well as for the community of concern (target population). The relationship between these variables related to drug use (i.e., ancillary variables) and actual drug use can then be calculated for the calibration populations and the resulting linear interpolation applied to the target community. Simeone, Rhodes, and Hunt (1995) propose the use of this model to estimate the number of "hardcore" drug users for cities and to describe a strategy for obtaining the needed data and developing estimates.

    Synthetic estimates may employ data from a calibration population in which rates of drug use can be calculated by demographic characteristics (e.g., gender, ethnicity, socioeconomic status) and extrapolated to a target community for which rates of drug use are not known, but the composition of the community by demographic characteristics is known. In this way, rates of drug use may be developed for subpopulations and for the full population of the target community.

    Using a comparable strategy, Kandel and Yamaguchi (1985) calculated "hazard rates" for initiation of different drugs (i.e., the incidence expected over a 12-month period), in accord with data regarding drug use in relation to age and gender. In a related effort, Kandel and Davies (1992) explored the predictor variables that might be employed to project rates of marijuana initiation as well as rates of progressive use of marijuana. Indeed, the variables associated with the adoption of drug and alcohol use, and of protection against that use, have been comprehensively described (Hawkins, Catalano, & Miller, 1992) and explored in general population models (Newcomb, 1992) and in models applied to specific subpopulations (Brunswick, Messeri, & Titus, 1992); thus it may be feasible to explore estimation strategies for incidence as well as prevalence and thereby clarify the prevention needs of selected populations.

    The accuracy of synthetic estimates depends on the comparability of the calibration population to the target population. As described by Wickens (1993), there is a risk that target and calibration communities may differ in ways that compromise accurate estimation. Thus, variables such as drug availability, police presence, treatment availability, prevention services, and community attitudes toward drug use may exist between communities, reducing their comparability. In addition, Kimmel (1992) notes that drug use patterns may vary between communities in ways unrelated to their demography such that amphetamine use may be prevalent in one community and PCP in another despite apparent similarities in population characteristics.

    As described by Hser (1993a, 1993b) and Wickens (1993), drug use prevalence in a community also can be estimated where the frequency of entry into a selected data system is known for some portion of the drug-using population—provided that the data are seen as following a Poisson distribution. That is, if the population can be assumed to be homogeneous and rates of entry can be seen as largely constant over time independent of the individual or of extraneous events, an estimate can be made of the portion of the population that has not entered the data system based on the numbers and frequency of entry of those who have, and thereby an estimate can be made of the total population. The result is a truncated Poisson estimate of population size. Homogeneity among population members is a particular concern (Wickens, 1993). Individuals who do not enter into the data system may differ in important ways from those who do, and/or those with varying frequencies may differ from each other, leading to an inaccurate estimate of the unobserved portion of the population.

    Multiple-capture models for estimating drug use prevalence use findings for individuals who have an opportunity to enter one or more data systems over time (Brecht & Wickens, 1993; Frank, Schmeidler, Johnson, & Lipton, 1978; Wickens, 1993; Woodward, Bonett, & Brecht, 1985). Estimation procedures then involve the calculation of the unknown (i.e., unobserved) portion of the population based on statistical models applied to the observed entries into data systems over time. Again, a Poisson distribution is seen as governing the distribution of drug use cases, and the assumptions underlying the Poisson distribution are seen as operative.

    System dynamics models (Homer, 1993; Wickens, 1993) explore prevalence in the context of the system dynamics in which drug use occurs. Thus, as described by Wickens, "an estimate of the prevalence of drug use might be made in the context of a description that includes measures of drug distribution, drug consumption, and the societal response to consumption and use" (p. 211). Four types of variables are involved in constructing the model. Exogenous variables involve quantitative data available with regard to drug use (e.g., drug arrests). Level variables represent relevant but unavailable data (e.g., numbers of drug users). Rate variables describe the rate of change over time of the level variable. Constants are quantitative variables that govern the connections between level variables (e.g., constants would be employed to relate change in drug availability to change in drug-user patterns). Formulas are then developed showing rates of change of level as functions of exogenous and level variables and of constants. Wickens suggests that system dynamics analysis lends itself best to policy analysis.

    A policy analysis strategy is also described by Kahan, Rydell, and Setear (1995), in this instance making use of a computer model allowing participants to test the effectiveness and measure the costs of control and prevention strategies designed to affect rates of heavy and light drug users in a hypothetical community as well as affecting initiation and transitions within drug use. The seminar gaming initiative they describe in association with this computer modeling lends itself to planning initiatives in which data, available from the community sources described above, are used in conjunction with findings from prevention evaluation research. Thus, differing scenarios of community prevention might be tested relative to data appropriate to that community.

Needs Assessment Strategies: Ethnographic Measures

    As described by Feldman and Aldrich (1990), ethnographic research involves the study of social phenomena from the viewpoint of the individual experiencing those phenomena. Most typically, the tools of the ethnographer are observation and open-ended questioning of members of the group or culture under observation (i.e., fieldwork involving qualitative rather than quantitative methodology). Ethnographic methods become significant where the population of concern is not readily accessible for more usual survey methods (i.e., can be described as a "hidden population"), or where the functioning of groups, or of individuals within groups, cannot be detailed through quantitative methodology (Lambert, 1990). Individuals engaged in illicit behaviors cannot be sampled in a manner that permits representativeness on the one hand or study of social and commercial interactions in the comparative comfort of a university laboratory on the other. Researchers enter the drug users' world and seek out individuals and situations that will allow data collection regarding typical events and people without claim to an unattainable representativeness.

    Thus, runaway youth cannot be studied in a manner that permits both probability sampling and easy study of social and commercial interactions. Nonetheless, ethnographers entering and reporting the world of the runaway adolescent (i.e., drugs used, frequency of use, situations determining use) may develop valuable data for constructing innovative prevention strategies specific to that population. The use of key informants is sometimes described as critical to such study (Adler, 1990; Goldstein, Spunt, Miller, & Belluci, 1990). Key informants are a major source of information about the behaviors or events in question and can provide entree to others in the community being studied. Thus, the key informant in this instance is a study subject with some standing in the community. Key informants can provide information regarding the nature and functioning of the drug culture and can facilitate the recruitment of additional subjects for study.

    An advantage of ethnographic study is that ethnographers obtain information directly from an otherwise inaccessible population. A disadvantage is that data collected can never be assumed to represent more than the individuals or locales selected. Also, the interpreting and reporting of that data may be selective in association with the theoretical orientation and beliefs of the ethnographer, although strategies have been developed to provide safeguards regarding the reliability and validity of ethnographic data (Fritz, 1990).

Assessing Community Resources to Provide Prevention Services

    The determination of community resources in terms of drug abuse prevention services demands assessments of both current activities (i.e., space, staff, and money) and attitude (i.e., the willingness to provide prevention services). The former, at least, can be determined largely by use of questionnaires, records review, and observation. Care should be taken to sample individuals who are knowledgeable about their agencies and who have significant administrative responsibility in those organizations. Interviewers should represent a broad-based community group rather than the narrow interests of drug abuse prevention agencies. Oetting and colleagues (1995) describe an interview strategy involving the sampling of a broad range of community "gatekeepers" that is designed to allow the community to be characterized in terms of attitude (i.e., readiness to undertake drug prevention programming). Using the interview data collected, beliefs about the community’s readiness for prevention programs are captured on five rating scales, each of which makes use of empirically determined anchor statements.

    The assessment of attitudes and, by extension, of the openness of community service providers to make available prevention services can be determined in interviews or questionnaires and also may be addressed in the context of focus groups designed to bring together relevant community members to explore issues in providing prevention services. The use of focus groups has several advantages. It can set in motion a process involving not only the elaboration of shared concerns, but the exploration of possible solutions. There is an advantage to discussion of new initiatives in a public forum. Thus, the commitment to explore a particular strategy or to designate an area for study is a commitment made publicly.

    It should be apparent that the assessment of prevention resources, like the assessment of prevention needs, must be undertaken by a community group or coalition that possesses the will and authority to command cooperation in the assessment process and to provide leadership to the process of systems change and expansion. In short, assessments of community prevention needs and resources are best underwritten by a community group that understands its role to be that of an agent of change, has the authority to act in that role, and awaits the results of those assessments in order to take remedial action on behalf of the community.

Conclusions

Selecting an Assessment Strategy

    A needs assessment strategy is determined by the questions being asked, the data sources available, and the resources that exist for making that assessment. Where the concern is with understanding the prevention needs of the community, information regarding emergency room admissions and medical examiner cases are likely to be less helpful than a survey of community households or of school-aged populations supplemented by the use of problem-oriented measures focused on youth, such as studying drug use by juvenile offenders.

    Surveys employing probability sampling are likely to be the most costly assessment strategies available. Alternatively, surveys involving nonprobability sampling can be employed to explore drug use in the health care, criminal justice, and social service systems. As discussed above, the more data sources (i.e., the more populations for study), the more confidence that can be placed in the trends identified.

    Finally, emphasis should be placed on the importance of testing and refining needs estimation models. Ultimately, the greatest utility of the data collection systems described may come in their capacities to generate reliable estimates of community need, through the use of that data in estimation models and through the use of simulation models in the study of prevention strategies designed to affect the initiation and/or escalation of drug taking.

Reporting the Findings of Needs Assessment Study

    The findings from a prevention needs assessment study should be reported in a manner that permits their use to achieve community change. The findings must be clearly grounded in science (i.e., must possess credibility) but must be stated in a language and format that permit their effective use by a community group or coalition. Additionally, the findings from a needs assessment must be released in a timely manner. Typically, there is a window of opportunity to produce change in a community that may be tied to political forces, to the timing of budgetary decisions, or to other issues.

    Disseminating study findings can be undertaken through a combination of oral presentations to the community group under whose auspices the needs assessment has been conducted and written materials to establish a permanent record and reference source for the community. Both the presentation and the written materials should make substantial use of clearly articulated tables and figures.

    Typically, programmatic change is a distant goal of research and often depends on the fortuitous use of findings published or reported by the investigator. In that paradigm, the investigator's responsibility is discharged with the appearance of study findings in the professional literature or at a scientific conference. Needs assessment carries a differing set of responsibilities for the investigative team. In the instance of prevention needs assessment, responsibility can be discharged only consequent to the acceptance and understanding of study findings by the sponsoring community group. A successful study outcome is less a matter of academic research results and more the initiation of community change.

References

Adler, P. (1990). Ethnographic research on hidden populations: Penetrating the drug world. In E. Y. Lambert (Ed.), Interpretation of data from hidden populations (pp. 96-112). Washington, DC: U.S. Government Printing Office.

American Management Association. (1995). 1995 AMA survey on workplace drug testing and drug abuse policies – Summary of key findings. New York: Author.

Aquilino, W. S. (1992). Telephone versus face-to-face interviewing for household drug use surveys. International Journal of the Addictions, 27, 71-91.

Aquilino, W. S., & LoSciuto, L. (1989). Effects of mode of data collection on the validity of reported drug use. Conference proceedings: Health survey research methods. Washington, DC: U.S. Government Printing Office.

Boyer, J. F., & Langbein, L. I. (1991). Factors influencing the use of health evaluation research in Congress. Evaluation Review, 15, 507-532.

Bray, R. M., Guess, L. L., Mason, R. E., Hubbard, R. L., Smith, D. G., Marsden, M. E., & Rachal, J. V. (1983). Highlights of the 1982 Worldwide Survey of Alcohol and Nonmedical Drug Use Among Military Personnel. Research Triangle Park, NC: Research Triangle Institute.

Bray, R. M., Guess, L. L., Mason, R. E., Hubbard, R. L., Smith, D. G., Marsden, M. E., & Rachal, J. V. (1986). Highlights of the 1985 Worldwide Survey of Alcohol and Nonmedical Drug Use Among Military Personnel. Research Triangle Park, NC: Research Triangle Institute.

Brecht, M.-L., & Wickens, T. D. (1993). Application of multiple-capture methods for estimating drug use prevalence. Journal of Drug Issues, 23, 229-250.

Brunswick, A. F., Messeri, P. A., & Titus, S. P. (1992). Predictive factors in adult substance abuse: A prospective study of African American adolescents. In M. Glantz & R. Pickens (Eds), Vulnerability to drug abuse (pp. 419-472). Washington, DC: American Psychological Association.

Burt, M. R., & Biegel, M. M. (1980). Worldwide Survey of Nonmedical Drug Use and Alcohol Use Among Military Personnel: 1980. Bethesda, MD: Burt Associates.

Cone, E. J., Yousefnejad, D., Darwin, W. D., & Maguire, T. (1991). Testing human hair for drugs of abuse. II. Identification of unique cocaine metabolites in hair of drug abusers and evaluation of decontamination procedures. Journal of Analytical Toxicology, 15, 250-255.

DuPont, R. L., & Baumgartner, W. A. (1995). Drug testing by urine and hair analysis: Complementary features and scientific issues. Forensic Science International, 70, 63-76.

DuPont, R. L., Griffin, D. W., Siskin, B. R., Shiraki, S., & Katze, E. (1995). Random drug tests at work: The probability of identifying frequent and infrequent users of illicit drugs. Journal of Addictive Diseases, 14, 1-18.

Feldman, H. W., & Aldrich, M. R. (1990). The role of ethnography in substance abuse research and public policy: Historical precedent and future prospects. In E. Y. Lambert (Ed.), The collection and interpretation of data from hidden populations. NIDA Research Monograph 98 (pp. 12-30). Washington, DC: U.S. Government Printing Office.

Feucht, T. E., Stephens, R. C., & Walker, M. L. (1994). Drug use among juvenile arrestees: A comparison of self-report, urinalysis, and hair assay. Journal of Drug Issues, 24, 99-116.

Frank, B., Schmeidler, J., Johnson, B., & Lipton, D. S. (1978). Seeking truth in heroin indicators: The case of New York City. Drug and Alcohol Dependence, 3, 345-358.

Fritz, R. B. (1990). Computer analysis of quantitative data. In E. Y. Lambert (Ed.), The collection and interpretation of data from hidden populations. NIDA Research Monograph 98 (pp. 59-79). Washington, DC: U.S. Government Printing Office.

Gerstein, D. R., & Harwood, H. J. (1990). Treating drug problems (Vol. 1). Washington, DC: National Academy Press.

Gfroerer, J. C. (1991). Nature and extent of drug abuse in the United States. In National Institute on Drug Abuse (Ed.), Drug abuse and drug abuse research (pp. 13-29). Washington, DC: U.S. Government Printing Office.

Gfroerer, J. C., Gustin, J., & Turner, C. F. (1992). Introduction. In C. F. Turner, J. T. Lessler, & J.C. Gfroerer (Eds.), Survey measurement of drug use—Methodological studies (pp. 3-10). Washington, DC: U.S. Government Printing Office.

Gfroerer, J. C., & Hughes, A. L. (1992). Collecting data on illicit drug use by phone. In C. F. Turner, J. T. Lessler, & J. C. Gfroerer (Eds.), Survey measurement of drug use—Methodological studies (pp. 277-298). Washington, DC: U.S. Government Printing Office.

Goldberger, B. A., Caplan, Y. H., Maguire, T., & Cone, E. J. (1991). Testing human hair for drugs of abuse. III. Identification of heroin and 6-acetylmorphine as indicators of heroin use. Journal of Analytical Toxicology, 15, 226-231.

Goldstein, P. J., Spunt, B. J., Miller, T., & Belluci, P. (1990). In E. Y. Lambert (Ed.), The collection and interpretation of data from hidden populations. NIDA Research Monograph 98 (pp. 80-95). Washington, DC: U.S. Government Printing Office.

Hawkins, J. D., Catalano, R. F., & Miller, J. Y. (1992). Risk and protective factors for alcohol and other drug problems in adolescence and early adulthood: Implications for substance abuse prevention. Psychological Bulletin, 112, 64-105.

Homer, J. B. (1993). A system dynamics model for cocaine prevalence estimation and trend projection. Journal of Drug Issues, 23, 251-279.

Hser, Y. -I. (1993a). Prevalence estimation: Summary of common problems and practical solutions. Journal of Drug Issues, 23, 335-343.

Hser, Y. -I. (1993b). Population estimates of intravenous drug users and HIV infection in Los Angeles County. International Journal of the Addictions, 28, 695-709.

Hubbard, M. (1992). Laboratory experiments testing new questioning strategies. In C. F. Turner, J. T. Lessler, & J. C. Gfroerer (Eds.), Survey measurement of drug use—Methodological studies (pp. 53-84). Washington, DC: U.S. Government Printing Office.

Innes, C. A. (1988). Profile of state prison inmates, 1986. Bureau of Justice Statistics Special Report. Washington, DC: Department of Justice.

Johnson, T. P., Hougland, J. G., & Clayton, R. R. (1989). Obtaining reports of sensitive behavior: A comparison of substance use reports from telephone and face-to-face interviews. Social Science Quarterly, 70, 174-183.

Johnston, L. D., O'Malley, P. M., & Bachman, J. G. (1989). Drug use, drinking, and smoking: National survey results from high school, college, and young adults populations 1975-1988. Washington, DC: U.S. Government Printing Office.

Johnston, L. D., O'Malley, P. M., & Bachman, J. G. (1995). National survey results on drug use from the Monitoring the Future study, 1975-1994. Washington, DC: U.S. Government Printing Office.

Kahan, J. P., Rydell, C. P., & Setear, J. (1995). A game of urban drug policy. Peace and Conflict: Journal of Peace Psychology, 1, 275-290.

Kandel, D. B., & Davies, M. (1992). Progression to regular marijuana involvement: Phenomenology and risk factors in near-daily use. In M. Glantz & R. Pickens (Eds), Vulnerability to drug abuse (pp. 211-253). Washington, DC: American Psychological Association.

Kandel, D. B., & Yamaguchi, K. (1985). Developmental patterns of the use of legal, illegal, and medically prescribed psychotropic drugs from adolescence to young adulthood. In C. L. Jones & R. J. Battjes (Eds), Etiology of drug use (pp. 193-235). Washington, DC: U.S. Government Printing Office.

Kimmel, W. A. (1992). Need, demand and problem assessment for substance abuse services. Washington, DC: U.S. Government Printing Office.

Lambert, E. Y. (1990). The collection and interpretation of data from hidden populations. NIDA Research Monograph 98. Washington, DC: U.S. Government Printing Office.

LoSciuto, L., Aquilino, W. S., & Licari, F. C. (1993). Interviewing minority youth about drug use: Telephone vs. in-person surveys. In M. R. De La Rosa & J. R. Adrados (Eds.), Drug abuse among minority youth. NIDA Research Monograph 130 (pp. 201-223). Washington, DC: U.S. Government Printing Office.

Maryland State Department of Education. (1994). 1992 Maryland adolescent drug survey. Baltimore: Author.

McAuliffe, W. E., Breer, P., White, N., Spino, C., Goldsmith, L., Robel, S., & Byam, L. (1987). A drug abuse treatment and prevention plan for Rhode Island. Boston: Harvard School of Public Health.

McAuliffe, W. E., LaBrie, R., Mulvaney, N., Shaffer, H. J., Geller, S., Fournier, E. A., Levine, E., Wang, Q., Wortman, S. M., & Miller, K. A. (1994). Assessment of substance dependence treatment needs: A telephone survey manual and questionnaire (Rev. ed.). Cambridge, MA: National Technical Center for Substance Abuse Needs Assessment.

McLellan, A. T. (1991). Dual diagnosis: Drug abuse and psychiatric illness. In National Institute on Drug Abuse (Ed.), Drug abuse and drug abuse research (pp. 61-83). Washington, DC: U.S. Government Printing Office.

Mieczkowski, T., Barzelay, D., Gropper, D., & Wish, E. (1991). Concordance of three measures of cocaine use in an arrestee population: Hair, urine, and self-report. Journal of Psychoactive Drugs, 23, 241-249.

Mieczkowski, T., Landress, H. J., Newel, R., & Coletti, S. D. (1993, January). Testing hair for illicit drug use. National Institute of Justice Research in Brief, pp. 1-5.

Minugh, P. A. (n.d.). State substance abuse treatment needs assessment: Baseline evaluation. In National Technical Center (Ed.), Needs Assessment Alert, 2, 1-3.

National Institute on Drug Abuse. (1991a). National Household Survey on Drug Abuse: Population estimates 1991. Washington, DC: U.S. Government Printing Office.

National Institute on Drug Abuse. (1991b). Annual emergency room data 1990. Rockville, MD: Author.

National Institute on Drug Abuse. (1991c). Annual medical examiner data 1990. Rockville, MD: Author.

National Institute on Drug Abuse. (1993). Prevalence of drug use in the Washington, D.C. metropolitan area homeless and transient population: 1991. Rockville, MD: Author.

National Institute of Justice. (1995). Drug Use Forecasting—1994 annual report on adult and juvenile arrestees. Washington, DC: Author.

Newcomb, M. D. (1992). Understanding the multidimensional nature of drug use and abuse: The role of consumption, risk factors, and protective factors. In M. Glantz & R. Pickens (Eds), Vulnerability to drug abuse (pp. 255-297). Washington, DC: American Psychological Association.

Oetting, E. R., Donnermeyer, J. F., Plested, B. A., Edwards, R. W., Kelly, K., & Beauvais, F. (1995). Assessing community readiness for prevention. International Journal of the Addictions, 30, 659-684.

Pires, S. A., & Silber, J. T. (1991). On their own: Runaway and homeless youth and programs that serve them. Washington, DC: Georgetown University Child Development Center.

Regier, D. A., Boyd, J. H., Burke, B. Z., Locke, D. S., Rae, J. K., Myers, M., Kramer, L. N., Robins, D. B., & Karno, M. (1988). One-month prevalence of mental disorders in the U.S.—Based on five epidemiological catchment area sites. Archives of General Psychiatry, 45, 977-986.

Rotheram-Borus, M. J., & Koopman, C. (1991). Sexual risk behaviors, AIDS knowledge, and beliefs about AIDS among runaways. American Journal of Public Health, 2, 208-210.

Simeone, R. S., Rhodes, W. M., & Hunt, D. E. (1995). A plan for estimating the number of "hardcore" drug users in the United States. International Journal of the Addictions, 30, 637-657.

Substance Abuse and Mental Health Services Administration (SAMHSA). (1995). National Household Survey on Drug Abuse: Population estimates 1994. Rockville, MD: Author.

Task Force on Homelessness and Severe Mental Illness. (1992). Outcasts on main street. Report of the Federal Task Force on Homelessness and Severe Mental Illness. Washington, DC: Interagency Council on the Homeless.

Turner, C. F., Lessler, J. T., & Devore, J. (1992). Effects of mode of administration and wording on reporting of drug use. In C. F. Turner, J. T. Lessler, & J. C. Gfroerer (Eds.), Survey measurement of drug use—Methodological studies (pp. 221-244). Washington, DC: U.S. Government Printing Office.

Turner, C. F., Lessler, J. T., & Gfroerer, J. C. (1992). Survey measurement of drug use— Methodological studies. Washington, DC: U.S. Government Printing Office.

United Way of America. (1982). Needs assessment—The state of the art—A guide for planners, managers, and funders of health and human services. Alexandria, VA: Author.

Wang, W. L., & Cone, E. J. (1995). Testing human hair for drugs of abuse. IV. Environmental cocaine contamination and washing effects. Forensic Science International, 70, 39-51.

Wang, W. L., Cone, E. J., & Zacny, J. (1993). Immunoassay evidence for fentanyl in hair of surgery patients. Forensic Science International, 61, 65-72.

Wang, W. L., Darwin, W. D., & Cone, E. J. (1994). Simultaneous assay of cocaine, heroin and metabolites in hair, plasma, saliva, and urine by gas chromatography-mass spectrometry. Journal of Chromatography B: Biomedical Applications, 660, 279-290.

Watters, J., & Biernacki, P. (1989). Targeted sampling: Options for the study of hidden populations. Social Problems, 36, 416-430.

Wickens, T. D. (1993). Quantitative methods for estimating the size of a drug-using population. Journal of Drug Issues, 23, 185-216.

Willette, R. E. (1986). Drug testing programs. In R. L. Hawks & C. N. Chiang (Eds.), Urine testing for drugs of abuse (pp. 5-12). Washington, DC: U.S. Government Printing Office.