PPT Slide
Analysis of cluster RCTs.
492 patient RCT. Mortality was reduced from 36% (82/223) to 24% (67/269).
control 82 67.5 141 155.5 223
treated 67 81.5 202 187.5 269
?2 = Sum [(Observed - Expected)2/ Expected] / Design Effect
= [(82-67.5)2/(67.5) + (141-155.5)2/(155.5)]/C1 +
[(67-81.5)2/(81.5)+ (202-187.5)2/(187.5)]/C2
C1 = 1+(m1-1)?, C2 = 1+(m2-1)?
? = 0.023616322, m1 = 42.4, m2 = 50.8