The paper maintains that impact evaluation studies of programs serving handicapped infants and preschoolers should be restricted to scientifically defendable investigations. Specific types of impact studies and an evaluation process are suggested. It is suggested that program leaders should focus evaluation activities on the status of project…

This paper considers methodological issues related to the independent variable in early intervention research. Three standards are proposed: (1) use theory to guide research; (2) provide operational definitions of independent variables, quantify them, and describe how they relate to theory; and (3) measure treatment fidelity. Three levels of…

This paper describes the parallel treatments design, a nested single subject experimental design that combines two concurrently implemented multiple probe designs, allows control for effects of extraneous variables through counterbalancing, and replicates its effects across behaviors. Procedural guidelines for the design's use and issues related…

This paper describes guidelines for reporting findings from studies using single subject methods, an approach from which early intervention has benefited substantially. Guidelines address: the foundations of the study, what was done to whom under what situations, what the data say, and what the findings mean. (Contains references.) (DB)

Issues are raised about the Council for Learning Disabilities Research Committee's standards for describing research subjects, including justification for the recommended standards, relationship between description of subjects and probability of replication, and impact of the type of research on subject description standards. Recommendations are…

A review of 20 research studies on the use of constant time delay in teaching chained tasks is analyzed in regard to demographic variables (participants, settings), procedural variables (probe format, delay sessions), outcome measures (effectiveness, generalization), and methodological adequacy (dependent and independent variable reliability). (DB)