This editorial outlines the GATE approach to critical appraisal, illustrated throughout using the Heart and Estrogen/progestin Replacement Study (HERS), a randomised, double blind, placebo controlled trial of the effect of daily oestrogen plus progestin on coronary heart disease (CHD) death in postmenopausal women.3 A detailed critical appraisal of HERS using a GATE-based checklist is available online.4