When can study participants serve as their own controls,allowing early trends in the data to emerge?
A) Cross-sectional
B) Ex post facto
C) Retrospective
D) Longitudinal

Question

Quizplus · Accepted Answer

Correct D: In longitudinal studies,subjects serve as their own controls,and trends in the data can emerge.
Incorrect A: Cross-sectional design does not allow for intraparticipant comparisons because data are collected at one point in time.
Incorrect B: In ex post facto research,events have already occurred; intraparticipant comparison is not involved.
Incorrect C: Retrospective studies are similar to ex post facto research.In ex post facto research,events have already occurred; intraparticipant comparison is not involved.

When Can Study Participants Serve as Their Own Controls,allowing Early