Cumulative Instructional Time and Relative Effectiveness Conclusions: Extending Research on Response Intervals, Learning, and Measurement Scale.

Adapted alternating treatments designs were used to evaluate three computer-based flashcard reading interventions (1-s, 3-s, or 5-s response intervals) across two students with disabilities. When learning was plotted with cumulative instructional sessions on the horizontal axis, the session-series graphs suggest that the interventions were similarly effective. When the same data were plotted as a function of cumulative instructional seconds, time-series graphs suggest that the 1-s intervention caused the most rapid learning for one student. Discussion focuses on applied implications of comparative effectiveness studies and why measures of cumulative instructional time are needed to identify the most effective intervention(s).Comparative effectiveness studies may not identify the intervention which causes the most rapid learning.Session-series repeated measures are not the same as time-series repeated measures.Measuring the time students spend in each intervention (i.e., cumulative instructional seconds) allows practitioners to identify interventions that enhance learning most rapidly.Student time spent working under interventions is critical for drawing applied conclusions.

Learning rates and known-to-unknown flash-card ratios: comparing effectiveness while holding instructional time constant.

Using alternating treatments designs, we compared learning rates across 2 computer-based flash-card interventions (3 min each): a traditional drill intervention with 15 unknown words and an interspersal intervention with 12 known words and 3 unknown words. Each student acquired more words under the traditional drill intervention. Discussion focuses on the need to account for instructional time when learning procedures are evaluated and compared.