|Principal strata according to potential behavior in each source of noncompliance (alternative version of Table1)|
|Strata||Behavior pattern in noncompliance sources 1, 2 and 3a||Treatment assigned and received for subject R in corresponding stratum|
|Compliers||Yes, no, no||Ri(Ti) = Ti|
|Yes, yes, no|
|Yes, yes, yes|
|Yes, no, yes|
|Always takers||No, yes, no||Ri(Ti) = 1|
|No, yes, yes|
|No, no, yes|
|Never-takers||No, no, no||Ri(Ti) = 0|
*As the trial is blinded, there are no defiers, as subjects cannot systematically take the opposite treatment; **Ri = treatment received, Ti = treatment assigned (0 = placebo, 1 = calcium); asources of (non)compliance: 1, taking >80% of pills assigned; 2, collateral treatment involving substantial calcium indicated by physician; 3, self-indicated collateral treatment involving substantial calcium.
Seuc et al.
Seuc et al. Trials 2013 14:78 doi:10.1186/1745-6215-14-78