From: Health services changes: is a run-in period necessary before evaluation in randomised clinical trials?
Mean (SD), number of telephone calls
Run-in period N = 759
Main trial N = 1236
PCT
A
31 (12.2), 190
23 (9.3), 395
B
29 (11.1), 181
27 (9.8), 290
C
38 (12.7), 255
30 (15.5), 298
D
23 (7.3), 133
19 (7.5), 253