We have a set of tools for estimating sample sizes.
Sample-size calculator for a diagnostic-accuracy study (Buderer 1996). Computes the number of diseased and non-diseased participants needed to estimate sensitivity and specificity with a target precision.
Sample-size calculator for logistic regression — events-per-variable rule plus the Hsieh (1989) formula. Plain-language inputs and a copy-ready methods paragraph.
Sample-size calculator for estimating a single proportion or prevalence with a desired margin of error. Includes design effect and finite-population correction.
Fast, MMed-friendly sample-size calculator for comparing two independent means (two-sample t-test). Plain-language inputs, citations, and a copy-ready methods paragraph.
Fast, MMed-friendly sample-size calculator for comparing two independent proportions or rates. Plain-language inputs, citations to support each assumption, and a copy-ready methods paragraph.