Table 1

Principal strata and sources of (non)compliance
Experimental group (calcium) Control group (placebo)
Source of (non) compliancea Taking >80% of tablets assigned Physician indicated collateral treatment involving substantial calcium Subject self-indication collateral treatment involving substantial calcium Taking >80% of tablets assigned Physician indicated collateral treatment involving substantial calcium Subject self-indication collateral treatment involving substantial calcium
Strata
Compliers Yes No No Yes No No
Yes Yes No Yes Yes No
Yes Yes Yes Yes Yes Yes
Always- takers Yes No Yes Yes No Yes
No Yes No No Yes No
No Yes Yes No Yes Yes
No No Yes No No Yes
Never-takers No No No No No No
Defiers*

*As the trial is blinded, there are no defiers, as subjects cannot systematically take the opposite treatment. If a subject decides not to take the pills (treatment) assigned, she belongs to the never-takers stratum. Compliers are subjects who always take the treatment assigned.

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

Open Data