Table 6 Relative decrease in sample size given various scenarios for increasing the number of baseline (p) or follow-up (r) measures.

pre

post

mix

Change from

Change to

Sample size reduction

No. of baseline measures (p)

No. of follow-up measures (r)

No. of baseline measures (p)

No. of follow-up measures (r)

0.7

0.7

0.5

1

1

1

4

30%

4

1

10%

4

4

40%

4

4

4

7

7%

7

4

3%

7

7

10%

7

7

7

14

5%

14

7

2%

14

14

8%

14

14

28

28

4%

0.5

0.5

0.5

1

1

1

4

50%

4

1

20%

4

4

70%

4

4

4

7

24%

7

4

17%

7

7

40%

7

7

7

14

27%

14

7

22%

14

14

48%

14

14

28

28

49%

0.9

0.9

0.8

1

1

1

4

21%

4

1

14%

4

4

35%

4

4

4

7

5%

7

4

3%

7

7

8%

7

7

7

14

3%

14

7

3%

14

14

6%

14

14

28

28

3%