Of the major extraneous variables discussed in this chapter, which is most likely a source of confounding in an interrupted time-series design?
A) participant expectations
B) history
C) attrition
D) regression

Question

Quizplus · Accepted Answer

History effects refer to events that occur during the course of a study which can influence the outcome independently of the experimental manipulation. In an interrupted time-series design, where observations are made over time before and after an intervention, any external event or change occurring concurrently with the intervention can confound the results, making it difficult to attribute changes in the outcome directly to the intervention.

Of the Major Extraneous Variables Discussed in This Chapter, Which