Radio Services--Post-TV (1946-1984)
A written diary of a family's or person's listening experience for a complete week, returned by mail, was long a measurement technique without an advocate. Unlike the telephone recall, the telephone coincidental, the meter, and the roster recall, no syndicated radio diary service emerged to market this technique.
James Seiler, an early pioneer of the diary technique for radio, used that experience in developing the household television diary he employed when he formed the American Research Bureau (ARB) in September 1949. Seiler thereby joined those individuals who championed their individual technique, but it was not until 1967 that ARB began its syndicated radio diary service.
The diary requires the respondent (either individual or household member) to enter his or her listening activity throughout a prescribed time period in a booklet supplied by the rating service. Most diaries are kept for 7 days, but there are variants from 1 to 14 days. Diary keepers can be recruited by mail, telephone, or personal interview or in combinations of these approaches.
The diary, because it is self-administered, has never been accepted as being on a par with the coincidental or the meter in terms of accuracy. People can forget to record all listening or make entries well after the listening event and commit errors in time, program name, channel number, or call letters. Errors of commission are also possible, in which the respondent fills in the diary either ahead of time or after the fact with "usually tuned programs" rather than actual behavior. The possibility that diary keepers want to please or "look good" can influence their entries, a conditioning element that is less prevalent in most other techniques.