As. Rigby et A. Vail, STATISTICAL-METHODS IN EPIDEMIOLOGY - II - A COMMONSENSE APPROACH TO SAMPLE-SIZE ESTIMATION, Disability and rehabilitation, 20(11), 1998, pp. 405-410
Purpose: It has been argued, by many, that mathematical formulae for e
stimating sample size are unnecessarily complex, so much so that resea
rchers may be reluctant to seek statistical advice. Method: This paper
reviews methods of sample size estimation arguing that two formulae (
one based on comparison of proportion of 'successes', the other based
on comparison of means of normally distributed data) suffice for many
situations. This paper argues the case by taking examples drawn mainly
from clinical trials research. However, the methods outlined can also
be used in epidemiology specifically in both case-control and cohort
studies with no loss of information. Results: For the situations outli
ned, worked examples are provided. Conclusions: Sample size estimation
need not necessarily be a complex process. Simple techniques exist wh
ich enable the clinician and the statistician to work together. Contin
ued dialogue between both parties is required so that good ideas do no
t go to waste.