The effect of a direct payment or a lottery on questionnaire response rates: a randomised controlled trial.
Roberts
P J
PJ
Seven Brooks Medical Centre, Atherton.
Roberts
C
C
Sibbald
B
B
Torgerson
D J
DJ
D000328:Adult; D000368:Aged; D004739:England; D005260:Female; D006306:Health Surveys; D006801:Humans; D008593:Menopause; D008875:Middle Aged; D016017:Odds Ratio; D012201:Reward; D011795:Surveys and Questionnaires