Explains the characteristics and importance of random assignment in experimental research on education. Considers factors supporting causal inferences, the nature of "assignment units," differences between random sampling and random assignment, the characteristics of randomization tests, forms of random assignment, and effects of experimental…

This paper identifies methodological and practical problems in studies of child maltreatment, including developing classification schemes for multiple forms of maltreatment; distinguishing between chronic maltreatment and isolated incidents; choosing criteria for selecting comparison groups; determining whether comparison groups have experienced…

It is difficult to conduct randomized field experiments. In the past decade, the use of alternative randomization plans and incentives has contributed to their operational feasibility; legal, ethical, and professional arguments for experimentation have matured; and expectations have become better aligned with practical constraints that are likely…

This commentary on EC 605 442, which indicated long-term gains for children with autism who experienced intensive behavioral intervention as preschoolers, questions the magnitude of the student changes and their significance, because of concerns about the representativeness and comparability of the sample group and the failure to measure skills…

This commentary on EC 605 442, which indicated long-term gains for children with autism who experienced intensive behavioral intervention as preschoolers, emphasizes the need for replication. The replication study should use random assignment to experimental and control groups, a larger sample of cases, standard diagnostic instruments to delineate…