California Drug and Alcohol Treatment Assessment (CALDATA-1991-1993)

Parent Series Details:

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Study Details:
The California Drug and Alcohol Treatment Assessment (CALDATA) was designed to study the costs, benefits, and effectiveness of the state's alcohol and drug treatment infrastructure (recovery services) and specifically to assess (1) the effects of treatment on participant behavior, (2) the costs of treatment, and (3) the economic value of treatment to society. Data were collected on participants (clients) across four types of treatment programs, or modalities: residential, residential "social model," nonmethadone outpatient, and outpatient methadone (detoxification and maintenance). Data were collected in two phases. In Phase 1, treatment records were abstracted for clients who received treatment or were discharged between October 1, 1991, and September 30, 1992. In Phase 2, these clients were located and recruited for a follow-up interview. The CALDATA design and procedures included elements from several national treatment outcome studies including the Drug Services Research Survey, Services Research Outcomes Study, National Treatment Improvement Evaluation Study, and Drug Abuse Treatment Outcome Study. The record abstract was designed to collect identifying and locating information for interview reference during the personal interviewing phase. The abstract also collected demographic, drug, or alcohol use, and treatment and service information. The follow-up questionnaire covered time periods before, during, and after treatment and focused on topics such as ethnic and educational background, drug and alcohol use, mental and physical health, HIV and AIDS status, drug testing, illegal activities and criminal status, living arrangements and family issues, employment and income, and treatment for drug, alcohol, and mental health problems. Drugs included alcohol, barbiturates, benzodiazepines, cocaine powder, crack, downers, hallucinogens, heroin, illegal methadone, inhalants, LSD, marijuana/hashish/THC, methamphetamines and other stimulants, narcotics, over-the-counter drugs, PCP, ritalin or preludin, and sedatives/hypnotics. CALDATA was originally known as the California Outcomes Study (COS).

Study Scope

Time period: 
Collection date: 
Geographic coverage : 
Unit of observation: 
individual, facility
Data types: 
survey data
All clients receiving recovery services in the four treatment modalities included in the study from California-based treatment providers known to the California Alcohol and Drug Data System (CADDS) as of September 1992. The CADDS programs include all prov
The study was conducted by the National Opinion Research Center at the University of Chicago and Lewin-VHI, Inc., Fairfax, Virginia, and Corte Madera, California.
The original data collection also included data on the treatment facilities. However, these data are not being released, per the data producers.
While 1,859 clients participated in the follow-up interview, 33 interviews were completed too late to be included in the study's final report. These cases are also excluded from the public use dataset, yielding a total of 1,826 cases.
Subject Terms: 
  • alcohol
  • cocaine
  • cost effectiveness
  • drug treatment
  • drugs
  • employment
  • hallucinogens
  • heroin
  • illegal activities
  • inhalants
  • intervention
  • marijuana
  • mental health
  • methadone
  • methadone maintenance
  • methamphetamines
  • physical health
  • program evaluation
  • substance abuse
  • substance abuse treatment
  • treatment costs
  • treatment programs

Study Methodology

CALDATA employed a multistage stratified sample design consisting of three stages. In the first stage, the state was stratified geographically into four regions to ensure state-wide coverage. Counties within these strata were randomly selected, with large counties being selected with certainty and small counties being clustered to provide sufficiently large sampling units. Selection chances for the non-certainty counties were weighted based on the number of participants. In the second stage of sampling, treatment providers were selected using similar principles of geographically balanced, size weighted random selection. In order to analyze each treatment modality, approximately equal numbers of facilities were selected across the modalities. As with counties, the smallest providers were clustered to provide adequately sized sampling units. In the third stage, client records were randomly chosen at each sampled facility with the number varying by the size of the provider and the extent to which the on-site listing of clients matched the number expected for that provider. Approximately 3,000 clients were selected for abstraction. Of these, 1,859 were recruited for the follow-up interview.
PADJ_WTD should be used as the default sampling weight for analyses.
Response rates: 
  • The overall CALDATA participant response rates are approximately 50 percent for the discharge sample and approximately 46 percent for the continuing methadone maintenance (CMM) sample. Response rates by modality in cooperating providers range from 56-61 percent, with the exception of methadone maintenance (76.5 percent).
  • 2008-10-07: New files were added. These files included one or more of the following: Stata setup, SAS transport (CPORT), SPSS system, Stata system, SAS supplemental syntax, and Stata supplemental syntax files, and a tab-delimited ASCII data file.
Extent of processing: 
  • Performed consistency checks.
  • Standardized missing values.
  • Created online analysis version with question text.
  • Performed recodes and/or calculated derived variables.
  • Checked for undocumented or out-of-range codes.

Study Bibliography