|
Sample sizes for various combinations of baseline (p) and follow-up (r) measures. Correlations for pre, post and mix are 0.5, 0.5 and 0.5. Results given relative to a trial with a single baseline and follow-up measure. |
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| Number of baseline measures (p) |
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| No. of follow-up measures (r) |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
12 |
15 |
| 1 |
100% |
89% |
83% |
80% |
78% |
76% |
75% |
74% |
73% |
73% |
72% |
71% |
| 2 |
67% |
56% |
50% |
47% |
44% |
43% |
42% |
41% |
40% |
39% |
38% |
38% |
| 3 |
56% |
44% |
39% |
36% |
33% |
32% |
31% |
30% |
29% |
28% |
27% |
26% |
| 4 |
50% |
39% |
33% |
30% |
28% |
26% |
25% |
24% |
23% |
23% |
22% |
21% |
| 5 |
47% |
36% |
30% |
27% |
24% |
23% |
22% |
21% |
20% |
19% |
18% |
18% |
| 6 |
44% |
33% |
28% |
24% |
22% |
21% |
19% |
19% |
18% |
17% |
16% |
15% |
| 7 |
43% |
32% |
26% |
23% |
21% |
19% |
18% |
17% |
16% |
16% |
15% |
14% |
| 8 |
42% |
31% |
25% |
22% |
19% |
18% |
17% |
16% |
15% |
14% |
13% |
13% |
| 9 |
41% |
30% |
24% |
21% |
19% |
17% |
16% |
15% |
14% |
13% |
13% |
12% |
| 10 |
40% |
29% |
23% |
20% |
18% |
16% |
15% |
14% |
13% |
13% |
12% |
11% |
| 12 |
39% |
28% |
22% |
19% |
17% |
15% |
14% |
13% |
12% |
12% |
11% |
10% |
| 15 |
38% |
27% |
21% |
18% |
16% |
14% |
13% |
12% |
11% |
11% |
10% |
9% |
Vickers BMC Medical Research Methodology 2003 3:22 doi:10.1186/1471-2288-3-22 |
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