Skip to main content

Table 5 Observed groups (according to treatment assigned received and pregnancy status) and corresponding principal strata

From: Intermediate outcomes in randomized clinical trials: an introduction

  Description Principal strata under initial assumptions* Principal strata under additional assumption**
Randomized to calcium:
OBS(100) received placebo and non pregnant 1, 4 NA
OBS(101) received placebo and pregnant 2, 7 NA
OBS(110) received placebo and non pregnant 3, 9, 10, 15 3, 9, 10, 15
OBS(111) received placebo and pregnant 6, 12, 13, 16 6, 12, 13, 16
Randomized to Placebo:
OBS(000) received placebo and non pregnant 1, 2, 3, 6, 3, 6
OBS(001) received placebo and pregnant 4, 7, 9, 12 9, 12
OBS(010) received placebo and non pregnant 10, 13 10, 13
OBS(011) received placebo and pregnant 15, 16 15, 16
  1. OBS (ijk), observed women randomized to i (0 = placebo, 1 = calcium), receiving j (0 = placebo, 1 = calcium), and pregnant k (0 = no, 1 = yes). *Initial assumptions are assumptions 1 to 5 in Section “Noncompliance as intermediate outcome”; **additional assumptions a) and b) described in Section “Noncompliance and pregnancy as intermediate outcomes”.
  2. NA, the corresponding principal strata are empty under additional assumptions.