Are radio listening diaries accurate?
The first use of a diary to record radio listening was in April 1934 when NBC in the United States included it in an 'activity' diary placed with 3,042 housewives nationwide.1 Diaries were used intermittently over the next 30 or so years in the US but did not succeed in supplanting the dominant Hooper (telephone), Nielsen (Audimeter) and Pulse (personal interview) measurements as the 'official' industry currency until 1967.
Nielsen's US local television measurement service, launched in the nation's 30 largest cities in 1955, used diaries in conjunction with meters attached to the television set. The diaries also included measurement of local radio at first, although the radio part was discontinued in 1963.
Diaries continue (outside the largest cities) to be the most widely used source of audience data for US local television stations.