Telephone answering machines: the influence of leaving messages on telephone interviewing response rates.

We studied women 45-54 years of age from two communities who failed to return a mailed survey in an experiment to assess the impact on interviewing response rates of leaving messages on telephone answering machines at the time of telephone follow-up. There were 88 and 103 subjects assigned to the "message" and "no message" groups, respectively. After adjustment for age, interviewer, and community, leaving messages increased the rate of reaching a household by about 15% and improved the overall interviewing response rate by about 15% as well. This improvement was more apparent in women from the higher socioeconomic status community.