The complete assessment of the benefits of an intervention must include evidence of the effect on the patient’s health status and quality of life. Such evidence is usually based on self administered or interview administered questionnaires, which are increasingly referred to as patient reported outcome measures. Two linked papers (doi:10.1136/bmj.a1190; doi:10.1136/bmj.a3006) raise important questions regarding the standardised application of these measures in randomised controlled trials. The first used several patient reported outcome measures as end points in an international study of combined hormone replacement therapy.1 The second is a systematic review of randomised trials that included the short form 36 item (SF-36) health survey questionnaire as an outcome measure.2

Two broad types of patient reported outcome measures exist—those that …