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-administer ed 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 assi gned to either the written diary or the telephone interview conditions; que stion wording and format were identical in both conditions. Daily data were collected for a period of 8 weeks. Results indicate that although telephon e 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 participant s as self-administered diaries. Except for reports of drinking and vegetabl e consumption telephone and diary conditions did not differ in the amount o f behavior reported; more drinking and vegetable consumption ware reported with telephone interviews, however: Telephone interviews also imposed consi derably higher overall personnel costs.