Sample size requirements for case-control study designs.
BACKGROUND
Published formulas for case-control designs provide sample sizes required to determine that a given disease-exposure odds ratio is significantly different from one, adjusting for a potential confounder and possible interaction.


RESULTS
The formulas are extended from one control per case to F controls per case and adjusted for a potential multi-category confounder in unmatched or matched designs. Interactive FORTRAN programs are described which compute the formulas. The effect of potential disease-exposure-confounder interaction may be explored.


CONCLUSIONS
Software is now available for computing adjusted sample sizes for case-control designs.
Edwardes
M D
MD
Division of Clinical Epidemiology, Royal Victoria Hospital, Montreal, Quebec, Canada. michael.edwardes@clinepi.mcgill.ca
D016022:Case-Control Studies; D015233:Models, Statistical; D012107:Research Design / Q000706:statistics & numerical data*; D018401:Sample Size; D012984:Software / Q000706:statistics & numerical data