1TRIAD is the acronym for “Treating Inmates’ Addiction to Drugs.”

2An additional 257 men and 74 women – a total of 331 subjects – who were not released

to supervision or for whom information was not available from a Probation officer were also

included in analyses of arrests. 

14

CHAPTER 1: INTRODUCTION

In the late 1980’s, the Federal Bureau of Prisons (BOP) implemented a residential drug abuse

treatment program (DAP) designed to assist inmates struggling with drug problems. The

treatment strategy addressed inmate drug abuse by attempting to identify, confront, and alter the

attitudes, values, and thinking patterns that led to criminal and drug-using behavior. From that

initial effort, the program has grown to include an essential transitional component that keeps

inmates engaged in treatment as they return to their home communities.

To assess the effects of its DAP program, the BOP, in conjunction with the National Institute on

Drug Abuse (NIDA), initiated an evaluation project, which has become known as the TRIAD1

drug treatment evaluation project. The evaluation was a multi-site study that compared inmates

who received in-prison residential drug and alcohol abuse treatment to inmates who did not

receive such treatment. While initial plans called for an experimental design, we were not able to

implement random assignment procedures. Since inmates had to volunteer to participate in the

DAP program, we had to address the possibility that the DAP outcomes could be influenced by

selection bias. Thus, the analyses of the major DAP outcomes incorporated statistical procedures

to measure and adjust for selection bias. In addition, our analyses controlled for other predictors

of post-release outcomes. 

This report focuses on the effects of the BOP’s in-prison DAP on post-release drug use,

recidivism, employment, and halfway house placements, while controlling for a variety of other

factors related to treatment outcomes. The results contained in this report relate to inmates who

were released to community-based supervision between August 1992 and December 1997 and

assessed over a 3-year post-release period. The sample included 2,315 individuals — 1,842 men

and 473 women — for whom comprehensive data were available and who were released to

supervision.2 Our earlier preliminary report provided 6-month outcome results for 1,866 subjects

where we reported most results for men and women combined due to the limitations of the

sample size of women (see Pelissier et al., 1998). In contrast, the current 3-year outcome study

provides separate analyses for men and women.

We sampled treatment subjects from 20 different institutions, which represented three-quarters of

the institutions that were operating programs during our evaluation study, but only 40 percent of

the institutions that currently operate residential treatment programs. These prisons included all

security levels except maximum security, and they served both male and female populations. The

residential programs included two components of treatment — an in-prison component and a
15

transitional services component (as part of community placement and supervision). The in-prison

treatment programs consisted of two different levels of duration — 9-month programs (500

hours) and 12-month programs (1,000 hours). 

Male and female comparison subjects were drawn from more than 40 institutions, some of which

had residential drug abuse treatment programs and some of which did not. The comparison

subjects consisted of individuals who had histories of previous drug use and, therefore, would

have met the criteria for admission to the residential drug treatment programs. 

Our 3-year post-release results demonstrate positive effects of the BOP’s residential drug

treatment programs on the post-release outcomes of drug use and recidivism as measur ed by

arrests, and arrests or revocations first noted in the preliminary findings. These positive results

were statistically significant for men but not for women. 

Results showed that the approximately 763 male offenders who completed the residential drug

abuse treatment program and had been released to the community for up to 3 years were less

likely to be rearrested for a new offense, to be rearrested or revoked, or to test positive for drug

use than was a similar group of untreated.

The probability of rearrest or revocation within 3 years after release was 44.3 percent for male

treatment completers as compared to 52.5 percent for untreated male subjects. Although the

results for women were not statistically significant, the difference between the treated and

comparison group suggests that treatment helped to reduce recidivism among women. Among

women who completed residential drug abuse treatment, 24.5 percent were arrested for a new

offense or had their supervision revoked within 36 months after release compared to 29.7 percent

among untreated inmates. 

The probability of drug use was 49.9 percent for male treatment completers as compared to a

probability of 58.5 percent for untreated subjects. We also found that treated women had a lower

probability of drug use than untreated women (35.0 percent and 42.6 percent, respectively), even

though the results were not statistically significant.

The third outcome measure, post-r elease employment, revealed positive effects for women

completing treatment but not for men. This report contains two measures of post-release

employment, both of which differ from that used in our previous 6-month report that found no

positive effects of treatment on post-release employment for either men or women. Women

who completed treatment were more likely to be employed full-time during the entire postrelease period and had a higher employment rate (that is, the percent of post-release time

employed in any capacity) than the comparison group. Women who completed treatment were

employed 68.6 percent of the post-release period and untreated women were employed 59.1

percent of the time. Among men, those who completed treatment were employed 70.5 percent

of the time and untreated men were employed 68.6 percent of the time.

When considering a fourth measure of effectiveness — successful completion of halfway house
3

 In the BOP, referred to as a Community Corrections Center (CCC) placement.

4

 The Anti-Drug Abuse Act of 1986 laid the groundwork for the drug treatment programs,

and the Anti-Drug Abuse Act of 1988 contained provisions for the funding of these programs.

16

placements3 — results showed no positive effects of in-prison drug treatment for either men or

women. 

This report is the first of our 3-year outcome reports. Our second report will assess the role of

transitional services provided during halfway house placements for individuals who did not

receive residential in-prison drug treatment. It will also assess the role of post-release

treatment services, which are provided after release from BOP custody (that is, after release

from a halfway house) while under supervision of a U.S. Probation officer. Lastly, this report

will identify inter-institutional differences in treatment effectiveness. 

Background

A large proportion of State and Federal inmates have histories of substance abuse. A selfreport assessment of Federal inmates in 1989 indicated that between 30 and 44 percent had

substance abuse histories (Whittenberger, 1990). A survey of State and Federal prisoners in

1997 found that over 70 percent of Federal prisoners and over 80 percent of State prisoners

reported previous drug use (Mumola, 1999). Considerable evidence suggests that criminal

behavior is amplified during periods of moderate and heavy drug use (Anglin and Speckart,

1986; Anglin and Speckart, 1988; Ball et al., 1981; Nurco et al. , 1985; Nurco et al. , 1988;

Speckart and Anglin, 1985; Speckart and Anglin, 1986).

The BOP has provided drug abuse treatment in various forms for decades. Although the

number of drug treatment units in Federal institutions gr ew to a high of 33 in 1978, the

number of programs began to decline in the early-to-middle 1980’s due to changes in the

social and political climate (Wallace et al., 1991). However, with the passage of the Anti-Drug

Abuse Acts of 1986 and 19884

 and an increased emphasis on and resources for drug abuse

treatment, the BOP redesigned its drug treatment programs after careful review of drug

treatment programs nationwide.

The BOP’s renewed interest in prison-based drug treatment programs began in 1988 when

then-director J. Michael Quinlan organized a national drug conference. Immediately following

this conference, the BOP Executive Staff approved the establishment of five institution-based

residential drug abuse treatment programs. In the years to follow, similar programs were

established throughout the Federal prison system and, by January, 2000, 44 r esidential

programs were operational.

In 1989 the National Institute on Drug Abuse expressed interest in a comprehensive evaluation

of prison-based drug treatment programs, and the BOP submitted a research proposal for
17

evaluating drug treatment programs in the Federal system. That proposal resulted in the

signing of an interagency agreement between the BOP and NIDA in 1990 for a multi-site

evaluation of the BOP’s residential drug abuse treatment program, which eventually emerged

as the TRIAD project.

The objectives of the TRIAD evaluation project specified in the original evaluation proposal

submitted to NIDA in 1990 were:

 To conduct a process evaluation. This aspect of the evaluation would address the following

issues:

1) the nature of the services provided;

2) the characteristics of the service recipients; 

3) program staffing patterns; and,

4) implementation of residential drug treatment programs within a correctional

environment.

 To conduct an outcome evaluation. The most important objective was to assess the extent to

which in-prison residential treatment, reinforced by community-based aftercare services, could

reduce drug use and criminal behavior after release from prison. Specific questions were:

1) Who are the program participants? Does the program serve the most serious

offenders?

2) What are the different types of substance abusing offenders?

3) What types of incarcerated offenders are more likely to volunteer for in-prison drug

treatment programs?

4) Are the 12-month (1,000-hour) drug treatment programs more effective than the 9-

month (500-hour) programs?

5) What role do services provided after release from prison play in preventing relapse to 

drug use or criminal behavior?

6) Are there specific types of drug-abusing offenders who benefit more from participation

in the in-prison residential drug treatment?

7) What are the relative effects of pre-treatment characteristics, the treatment program,

and the post-release environment on the various outcomes?

Organization of the Report

This report is organized into eight chapters. Chapter 1 provides a brief introduction and

background to this evaluation project, as well as to this 3-year post-release outcome report. The

chapter concludes with synopses of the report’s remaining chapters.

Chapter 2 is divided into two sections. The first section discusses the nature of evaluation

research in an applied setting, with a focus upon what we view as the most significant
18

methodological problem — selection bias. Our goal is to represent the difficulties of applied

correctional research, to describe the organizational pressures that determine which inmates

receive treatment, to depict these influences in an understandable model of selection pressures,

and to offer potential solutions to these problems, both analytical and methodological. We

discuss the two different processes we used in our analyses to address the problem of selection

bias.

In the second section of this chapter, we use our model of selection pressures to critique the

research design, analyses, and interpretation of results contained in the most commonly cited,

related studies. Overall, our review suggests that methodological problems associated with

evaluating residential drug treatment programs create important obstacles to interpreting the

results of this research. We believe that, for the most part, the research we reviewed suffers from

inferential problems associated with disentangling treatment effects from selection bias effects.

We argue that it would be prudent to temper strong conclusions about successful treatment

outcomes — which are often portrayed in the literature — with a bit of skepticism, born from a

closer look at the methodological problems.

Chapter 3 provides a summary of the literature on gender differences within substance abusing

and criminal justice populations. This literature is important to understanding the selection of

predictor variables, to help provide an interpretation of the results, and to suggest the direction

for future research to enhance our understanding of gender differences in treatment needs and

treatment outcomes. 

Chapter 4 summarizes the evolution of the Bureau’s drug treatment programs from the

beginning of the TRIAD drug treatment evaluation project to the completion of the in-prison

data collection phase of the study. This summary details the nature and intensity of the

services received and the various pathways into tr eatment. That is, r esearch subjects may have

received drug treatment services while in prison, while housed in a halfway house (if

applicable), while under post-release supervision (if applicable), or during some combination

of the three. Chapter 4 also describes the various components of the BOP’s in-prison drug

treatment programs, as well as the treatment services available following release from an

institution. As is true for many major research efforts, changes in research design and data

collection procedures occurred throughout the project in order to adapt to changes in program

implementation. 

Chapter 5 describes the research design. After a summary presentation of the basic research

design, we provide information on the procedures used for selecting research subjects, the

resulting sample, the data collection instruments, and the data collection procedures. We

describe the differences between the selection of treatment and comparison subjects, as well as

the methods used to collect information at the various stages of a subject’s criminal justice

status. At any given time, he or she was either in prison, in a halfway house, terminated from

BOP custody without supervision, or terminated from BOP custody with supervision by a

probation officer. Chapter 5 concludes with listings and descriptions (when necessary) of all

the variables used in the analyses.
19

Chapter 6 contains a description of the subject sample. This chapter provides univariate

statistics for each of six subject groups – treatment and comparison subjects – by gender. The

primary purpose of these descriptive statistics is to provide the reader with a basic

understanding of the background characteristics of the subject groups, the treatment services

received, the type and level of supervision provided after release from prison and the postrelease outcomes. These six subject groups were:

inmates who completed a residential drug abuse treatment program; 

inmates who dropped out of a program;

inmates discharged for disciplinary reasons;

inmates who did not complete a program through no fault of their own; 

inmates from drug tr eatment sites who did not volunteer for treatment; and,

inmates who were housed at institutions at which there were no drug abuse treatment

programs offered. 

Chapter 6 is particularly relevant to service providers and others who want to know more

about the general nature of the drug abusing population being served by BOP drug abuse

treatment programs.

Chapter 7 contains results of analyses of treatment entry and treatment completion. An

understanding of treatment entry provides important information to treatment providers for

cases where program participation is voluntary in nature. Furthermor e, tr eatment-seeking

behavior within a prison setting is a neglected topic within the drug treatment field. In

addition, we provide the results for models of treatment entry and completion. These models

are vital for the subsequent outcome analyses described in Chapter 8.

Chapter 8, which describes the analysis and results, begins with a description of our outcome

measures: r ecidivism, drug use, employment and Community Corrections Center placement

failure. This is followed by a description of our three analytic strategies. Two of these analytic

strategies represent methods of addressing the problem of selection bias, a methodological

problem encountered often in treatment outcome studies. We continue with a presentation of

the consideration of missing data. Because listwise deletion — the deletion of a subject with a

missing value on one or more data elements — can result in a biased sample available for

analyses we imputed the missing values using various methods.

In this chapter, we describe the diagnostic tests for outcome model specification, when

applicable, and the steps taken in response to these tests. We then proceed to compare the

treatment effect across the various analytic str ategies and discuss the other significant predictor

variables highlighting gender differences. 

Chapter 9 provides a summary of the results. This discussion focuses upon the conclusions we

can make regarding the effectiveness of the Bureau’s drug abuse treatment programs. We seek

to identify consistencies in results across the various outcomes and, mor e specifically,

consistencies across the different analytic strategies for a particular outcome. Finally, this
20

chapter identifies the limitations of our conclusions, the issues to be presented in the second

report, and the issues important to future analyses.