The dillman total design survey method.

The Total Design Method (TDM) as offered by D.A. Dillman promises "guaranteed" 80% return rates for mail and telephone surveys. In a survey conducted in London, Ontario, a booklet-type questionnaire, introductory letter, return postcard and return stamped envelope were mailed to 185 family physicians. Non-responders were followed up one week after the initial mail-out with a reminder postcard, and three and seven weeks after the initial mail-out with replacement questionnaires. A return rate of 92.8% proved that the method was highly successful. The TDM is based on sound research principles and confirms that when attention is paid to administrative detail, high response rates can be achieved from difficult subjects.