Approaches to pretest-posttest analysis

[SR Millis]

I'm interested in doing an informal survey of preferred approaches to analyzing pretest-posttest data. Patients have been randomized to either a placebo group (coded 0) or medication group (coded 1). T1 represents performance on a cognitive measure at baseline before placebo/drug. T2 is the post-test performance on the same cognitive measure.

One could perform an ANCOVA (with t1 as covariate), analyze change scores (eg, paired t-test), use AUC, or use GEE. Which do you choose? Are there preferred alternatives?

Thanks for your input,
SR Millis

grp t1 t2
0 15 14
0 11 6
0 2 7
0 5 1
0 6 3
0 5 8
0 3 5
0 22 18
0 13 10
0 3 6
0 8 7
0 4 4
0 10 0
0 14 13
0 11 6
0 10 1
0 3 0
0 18 11
0 9 3
0 6 4
0 3 6
0 3 5
0 3 3
0 5 2
0 18 9
0 8 3
1 9 6
1 8 6
1 7 7
1 6 6
1 1 7
1 5 4
1 3 4
1 18 17
1 2 0
1 9 11
1 14 14
1 6 7
1 5 3
1 0 0
1 20 17
1 9 9
1 15 8
1 3 6
1 6 10
1 4 4
1 11 5
1 6 5


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