Dear Colleagues,
A student is evaluating a summer program for junior high students. One of
the goals was to raise 'self esteem.' Measures were taken before the
program, at the end, and a month later. He expected that the program would
be most effective for those who entered with especially low self esteem. He
divided the students into quartiles based on the pretest and compared these
subgroups on change. He found that his hypothesis was supported - there was
greatest positive change for those who entered in the lowest quartile.
However, further examination showed a clear 'regression toward the mean'
effect, including a small negative change for the group that entered in the
highest quartile. (The test does not have great reliability.)
Question: How should he analyze these data?
I would appreciate some discussion of this situation. Thank you.
Dale Berger
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