The relative costs and benefits of telephone interviews versus self-administered diaries for daily data collection

This article compares two methods of collecting daily data: self-administered diaries and telephone interviews. Study participants included 44 men and 56 women between the ages of 16 and 35 who participated in a larger study of drinking, drug use, and sexual activity. Participants were randomly assigned to either the written diary or the telephone interview conditions; question wording and format were identical in both conditions. Daily data were collected for a period of 8 weeks. Results indicate that although telephone interviews resulted in slightly more missed days of data collection, they generally yielded less item-level missing data, produced cleaner data and therefore were less costly to process, and were as palatable to participants as self-administered diaries. Except for reports of drinking and vegetable consumption, telephone and diary conditions did not differ in the amount of behavior reported; more drinking and vegetable consumption were reported with telephone interviews, however. Telephone interviews also imposed considerably higher overall personnel costs.