title: A method for estimating bias introduced into epidemiological investigations by those who refuse to participate.
abstract: Several methods have been suggested for estimating the error introduced into epidemiological investigations by potential participants who decline participation. As these could not be applied to our present epidemiological case-control breast cancer study, a new and simple method was developed based on information gathered from those controls who participated only relunctantly. A formula is given for calculating an adjusted mean for the sample and corresponding p-value. Our own data were used to illustrate the method. The calculations then indicated that those who declined participation were slightly selected in some aspects, but not to such a degree as to obscure or cause any significant differences between patient and control groups.
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008393:Marriage; D008572:Menarche; D008875:Middle Aged; D010358:Patient Participation; D011247:Pregnancy; D012424:Rural Population; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires