2014 Nielsen Audio Population Updates
November 7, 2013
Each year, effective with the October PPM and Fall diary books, updated population numbers are incorporated into Nielsen Audio’s radio audience estimates. Changes within a station’s key demographic can significantly impact its ratings, even if panelists’ or diarykeepers’ listening hasn’t changed at all.
The 2013 population estimates, last used in the September 2013 PPM and Summer 2013 diary surveys, were based on Census 2010 data that was projected to 2013. Beginning with the October 2013 PPM and Fall 2013 diary surveys, the population estimates are based on Census 2010 data projected to 2014.
Nielsen Audio uses population estimates in order to model their sample as similarly to the population as possible – demographically, ethnically, and geographically. For example, if 20% of a market’s population are Hispanic, Nielsen will attempt to compose its sample of 20% Hispanics.
Ideally, each meter or diary represents the same number of people in the metro as every other meter or diary. However, when Nielsen over- or under-samples a particular group, they employ weighting. This means that a meter or diary in an under-sampled group will represent more people than a meter or diary in an over-sampled group. In my example from the previous paragraph, if the market is 20% Hispanic but the sample is only 10% Hispanic, Nielsen would double the “value” of those meters or diaries so that reported radio estimates reflect listening from 20% Hispanics.
Due to weighting, stations whose audience is under-sampled may notice greater fluctuations in their data compared to stations whose audience is not under-sampled. If a panelist or diarykeeper with abnormal listening habits is from an under-sampled group, their meter or diary value will be more heavily weighted. This means that the abnormal listening habits are magnified. That’s why it’s so crucial to take a look at the population updates each year to see if there were any major changes in your station’s key demographics.
If you’re in a PPM market, your October book released last week. If you’re in a diary market, your Fall Arbitrends data releases this month, with the Fall book out in January
If you have any questions about how these population changes affect you, give us a shout. Research Director, Inc. clients will be receiving a breakout of the changes for their particular market.
-Anne Doyle, Production Manager