TELEPHONE VERSUS POSTAL SURVEYS OF GENERAL-PRACTITIONERS - METHODOLOGICAL CONSIDERATIONS

Background High response rates to surveys help to maintain the represe ntativeness of the sample. Aim. In the course of a wider investigation into counselling services within general practice it was decided to a ssess the feasibility of increasing the response rate by telephone fol low up of non-respondents to a postal survey. Method. A postal survey was undertaken of a random sample of 1732 general practitioners follow ed by telephone administration of the questionnaire to non-respondents . The identical questionnaire was administered by telephone to a separ ate random sample of 206 general practitioners. Results. Of 1732 gener al practitioners first approached by mail, 1683 were still in post of whom 881 (52%) completed the postal questionnaire and a further 494 (2 9%) the telephone interview. Of 206 general practitioners first contac ted by telephone, 197 were still in post of whom 167 (85%) completed i nterviews. Compared with doctors first approached by mail, those first approached by telephone were significantly more likely to report havi ng a partner with a special interest in psychiatry (P<0.01); and a gen eral practitioner, practice nurse or health visitor who worked as a co unsellor (P<0.01 in each case). A comparison of doctors first approach ed by telephone with those who completed telephone interviews after fa iling to respond to the postal questionnaire showed that postal non-re spondents were significantly less likely to report having a general pr actitioner, practice nurse, health visitor or community psychiatric nu rse who worked as a counsellor (P<0.01 in each case). Conclusion. Thes e findings suggest that non-response to the postal survey was associat ed with lack of activity in the study area. Telephone administration o f questionnaires to postal non-respondents increased response rates to above 80% but, as telephone administration enhanced the reporting of counsellors, a social desirability bias may have been introduced.