Comparison of the explicit timing and interspersal interventions: Analysis of problem completion rates, student preference, and teacher acceptability

Explicit timing and interspersal interventions were investigated using a within-subjects design with 45 third-grade students. A control assignment consisted of subtraction of a two digit number from a two digit number (i.e., target problem) and served as a baseline. An explicit timing assignment consisted of similar problems as those for the control assignment. The interspersal assignment consisted of similar problems as those for the control and explicit timing assignments with the addition of subtraction of a one digit number from a one digit number interspersed following every third target problem. Total problem completion rates, target problem completion rates, accuracy on target problems and students' rating regarding difficulty, time, effort, and preference between assignments for class work were collected. Student preference choices were analyzed for fit with the discrete task completion hypothesis. Three trials were administered. Results indicated that: (a) students completed more total problems during interspersal, (b) target problem completion rates were higher during explicit timing, (c) accuracy rates remained constant, (d) students rated the explicit timing assignment as requiring more time and being more difficult for all trials and as requiring more effort for trial 2 and 3, (e) students selected the interspersal assignment to do in class as compared to the explicit timing assignment for all trials, and (f) the data fit the discrete task completion hypothesis relatively well for all trials. Discussion focuses on comparing academic interventions based on problem completion rates, student preference, and acceptability data.