GfK currently holds the radio rating contract for audience measurement in Australia. A diary system is used for measuring audiences in the larger radio markets.
Eight surveys are done each year in each of the five major capital cities. These cities are surveyed for 41 weeks of the year. Each year 60,000 diaries are completed which make up the radio ratings.
Radio diary participants are geographically selected in proportion to the distribution of the population. Each market is split into geographic regions and sub-regions dubbed statistical local areas (SLAs). Each SLA is split further into interviewing areas or census collectors districts (CD's).
Homes are then statistically selected and approached within these CD's. A "single source lifestyle questionnaire" is enclosed in the diary. The diary contains relevant lifestyle and purchasing habits/intentions relating to the household.
One person more than 10 years of age living in the home is given a diary. Each person is required to record their radio listening in the diary for one seven-day period from Sunday through to Saturday.
The diary in each market is a "Sticker-Diary" listing stations available in each of the markets. Stations that are not listed can be added by the respondent, by adding the name of the station on a blank sticker. Each quarter hour of the day between midnight and midnight is listed. There are separate columns to indicate "place of listening".
Diaries are collected at the end of each week and, after a survey period, the completed diaries are processed to produce data relating to an average week of the survey period.