ABSTRACT
Design researchers are interested in devising and iterating innovative interventions to support student (and teacher) learning, particularly in situations where the extant research provides little guidance. In the practice of design research, many students and teachers participate in multiple forms or iterates of the designed artifact or emerging practice. Multiple iterates make it difficult to know which version of the artifact, or changed practice, caused the observed change, or learning, on the part of the participants. Logically, there is no counterfactual (e.g., control condition). From the perspective of data modeling and analysis, one option is to treat students as their own control. That is, researchers can look at student trajectories over time and ask whether the growth trajectory changes significantly with parallel changes that are occurring in the artifact or practice (that is being re-designed). Taking a longitudinal perspective can provide design researchers with insight and sources of evidence to support causal claims they could not otherwise entertain. This chapter will describe the use of an “interrupted time series research design” as a plan for the conduct of design research. This type of design offers strength and direction regarding the number of subjects and the spacing of time-points needed to buttress the design researchers’ efforts to warrant their claims for the effectiveness of their design interventions.
