Wagner Et Al

Multiple Choice

Wagner et al. (1988) used an interrupted times series design to examine changes in worker productivity after the institution of a worker incentive plan. In addition to measuring productivity, they also examined other information in order to rule out alternative explanations of their results. They were able to rule out _______ because _______.

A) history; no significant event occurred around the time of the program's start
B) instrumentation; the manner of measuring productivity didn't change
C) selection; of an absence of significant worker turnover
D) all of the above