WHAT SIZE SAMPLES FOR METHODS/MATERIALS EXPERIMENTS?

Careful planning of educational experiments includes decisions about the sample size to be used. This paper provides a guide to the minimum size of treatment groups, inferred from the relationships between pupil norms and norms for class averages of standardized achievement tests. With "highly effective" treatments and simple random assignment of subjects to conditions, 60 to 85 subjects is derived as the minimum number per group. With "moderately effective" treatments, the minimum number is 235 or more. Use of stratified samples reduces the minimum by fifteen to forty percent.     

Problems in interagency collaboration: Lessons from a project that failed

Several institutions (e.g., child welfare, police, court, health, education, social service) are necessarily involved in the management of child abuse in all communities. The need for better cooperation among them has been acknowledged; inquests into child deaths resulting from abuse have often attributed some blame to faulty communication and/or poor cooperation between the institutions. The Community Child Abuse Team (CCAT) Project was designed by these same institutions in Hamilton, Ontario, to maximize interagency collaboration. The hypothesis, that this "interagency collaboration" model would provide more efficient and effective services to abused children and their families, was never tested. During its 30 months of operation the CCAT program never materialized as planned and funding was terminated. This paper describes selected problems and issues that arose during the struggle to implement the project. The central problematic issue was control. Those responsible for the project lacked the power to insist that the design be adhered to during the initial stage.