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Table 1 Sample size calculations for detection of reductions in adverse event rates

From: Protocol for evaluation of the cost-effectiveness of ePrescribing systems and candidate prototype for other related health information technologies

Risk ratio Power (%) Sample size (total)
0.6 80 16,556
0.7 80 30,716
0.8 80 71,988
0.6 90 40,676
0.7 90 41,294
0.8 90 95,702
  1. Sample size calculations for detection of reductions in preventable adverse event rates in a simple comparison of two equally sized groups of patients – assumes a two-tailed alpha of 0.05 (without continuity correction) and a control probability of 1%. Results from STATA v12.0.