Radio Spot Length
Radio Recall Research, LLC (Media Dynamics, 2006) found in their recall studies that:
30 second radio ads generate about 80% of the proven recall of a 60 second ad
(60 second: 19.6% recall vs 30 second: 15.2% recall).
Allan (2007) found in his study that:
30s ads were significantly lower than 60s ads in: recall of brands, advertising message, and proven recall.
Alan (2007) recommends that the cost of a 30s ad could be 67% of a 60s ad with message recall paying 54% and proven recall paying 43%.
Results suggest primacy effect, with being the first or second in a pod as most effective no matter the commercial length.
Ad Format X Radio Length