Factors that influence the sample size necessary for longitudinal evaluations include the nature of the evaluation questions, nature of available comparison groups, consistency of the treatment in different sites, effect size, attrition rate, significance level for statistical tests, and statistical power. (Author/GDC)

Explores sequential assignment (SA) and treatment-as-usual (TAU) as two approaches to overcome many of the obstacles of random assignment in field studies of treatment efficacy. Substituting SA and TAU for the standard random assignment may introduce methodological impurities including certain limited biases. (SLD)

The 11 programs and sites participating in the Bureau of Justice Assistance (BJA) Intensive Supervision Demonstration Project are described. The demonstration was designed to assess the effects and costs of sentencing convicted felons to community-based programs. The evaluation by the Rand Corporation and data collection methods and random…

Six potential problems with the use of randomized experiments to evaluate programs in the field are addressed. Problems include treatment dilution, treatment contamination or confounding, inaccurate case flow and power estimates, violations of the random assignment processes, changes in the environmental context, and changes in the treatment…

A methodology is presented for collection of cost data in evaluation of community-level health interventions that coincides with the intervention implementation. The seven discrete steps of the analysis are described, and the Minimal Contact Education for Cholesterol Change study is used as an example of how the strategy is used. (SLD)

An evaluation of a North Carolina supervision program for juvenile offenders--the Intensive Protective Supervision Project--is presented. The program involves extensive and proactive contact between the court counselor, offender, and offender's family. Statistical and field-based evaluation suggest that the project is successful in preventing…