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Table 4 Baseline to post-randomisation follow-up correlations by post-randomisation follow-up time point

From: Sample size estimation for randomised controlled trials with repeated assessment of patient-reported outcomes: what correlation between baseline and follow-up outcomes should we assume?

Post-randomisation follow-up time point (months) Pearson baseline to post-randomisation follow-up correlation
Mean Median SD Minimum Maximum No. of correlations
0.25 0.48 0.48 0.44 0.17 0.79 2
1 0.37 0.39 0.28 0.09 0.64 3
1.5 0.49 0.45 0.12 0.33 0.70 14
2 0.55 0.56 0.12 0.26 0.82 34
3 0.48 0.50 0.15 −0.13 0.72 71
4 0.48 0.49 0.09 0.35 0.63 9
4.5 0.48 0.52 0.09 0.32 0.58 9
6 0.54 0.55 0.16 0.04 0.88 121
8 0.43 0.44 0.13 0.21 0.58 9
9 0.62 0.62 0.16 0.38 0.91 16
10 0.45 0.43 0.08 0.34 0.58 9
10.5 0.42 0.47 0.12 0.19 0.54 9
12 0.46 0.48 0.14 0.01 0.72 86
16.5 0.41 0.42 0.12 0.23 0.57 8
18 0.47 0.49 0.13 0.16 0.67 27
24 0.51 0.53 0.15 0.17 0.84 37