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Table 1 Statistical power (percentages) to detect a log-linear trend from various designs for 700 risk sets

From: Study design: Evaluating gene–environment interactions in the etiology of breast cancer – the WECARE study

     Counter-matching
   Random sampling CM 1:2 CM 2:1
2 Gy rate ratio Alla NCC 3 NCC 4 PN = 100%, PP = 100% PN = 90%, PP = 90% PN = 100%, PP = 100%
1.4 79 61 63 70 67 63
1.5 87 69 78 84 80 78
1.6 97 86 93 95 92 92
1.7 100 95 97 99 96 97
  1. CM 1:2, counter-matched design in which one member of the triplet is registry radiation treatment negative (RRT-) and two are registry radiation treatment positive (RRT+); CM 2:1, counter-matched design in which two members of the triplet are RRT- and one is RRT+; NCC 3, nested case-control study in which each case is randomly matched to two controls; NCC 4, nested case-control study in which each case is randomly matched to three controls; PN, predictive negative value; PP, predictive positive value. aFull cohort power where radiation dose is available for all controls in the risk set and used in the analysis; this is the upper limit on any case-control analysis.
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