Arbitron is a radio audience research company in the United States. It collects data on radio audiences similar to the data collected by Nielsen Media Research on television audiences.

Arbitron collects data by selecting a random sample of the population to maintain a written diary describing what radio programs they have listened to. For each selected household that agrees to participate, Arbitron sends a diary for each member of the household age 12 or older. Each person maintains a diary for one week, typically starting on a Thursday and ending the following Wednesday. At the end of the week, the diaries are mailed back to Arbitron. A new random sample is selected to participate each week.

The information collected is then sold to radio companies and advertisers. Information is collected and made available on a regional basis.

According to some critics, the data collected by Arbitron may not be as accurate as the data collected by Nielsen or other companies. Critics base their opinion mainly on two arguments. First, Arbitron's surveys have a relatively low response rate of approximately 30 percent. Second, the written diaries may not accurately reflect the programming actually listened to by the survey participant. For example, the participant may not remember exactly when they started or stopped listening, or they may forget to record an entry in the diary altogether.

See Also: Nielsen Ratings (for television programs)