Comparison of ‘Power for Randomized Clinical Trials’ to other public software programs.

Date last tested: 7/11/05

| CI%, n1, p1, n2, p2
Data input | 95%, 100, 20%, 200, 10%1 | 95%, 100, 10%, 200, 20% | 95, 474, 45%, 255, 35.29% | 95, 474, 35.29%, 255, 45%
software | Power | Power with continuity correction | Power | Power with continuity correction | Power | Power with continuity correction | Power | Power with continuity correction
OpenEpi | 67.23% | 60.14% | 59.21% | 52.41% | 71.88% | 69.11% | 72.91% | 70.15%
PEPI | 65.78% | 59.25% | 60.09% | 52.65% | 72.12% | 69.32% | 72.66% | 69.93%
EPI 505 | 67.1% | 59.3 | 59.1% | 52.6% | 71.7% | 69.2% | 72.7% | 69.8%

Confidence interval CI; sample size of treatment-1 ‘n1’; percent with outcome in treatment-1 ‘p1’; sample size of treatment-2 ‘n2’; percent with outcome in treatment-2 ‘p2’.

Reference:

· PEPI: Abramson JH and Gahlinger PM (2001). Computer program for epidemiologists: PEPI version 4.0. Sagebrush Press, Salt Lake City. Used POWR.EXE version 4.0.

· Epidemiology 505 - Emory University (version - 11 October 2000)