Back in December, 2014, the TAB (Traffic Audit Bureau) Board of Directors requested that the current definition for calculating digital spot ratings be replaced with a new definition that aligns more closely with those currently used by internet, mobile, and placed-based digital media.
This month, the TAB Board approved the proposed changes, moving TAB closer to a digital impression definition currently endorsed by the MRC, IAB, ARF and AAAA for internet, mobile, and placed-based media.
The changes hold true to the principles of TAB Out-of- Home Ratings, by maintaining a measure of precision provided by the original spot-by-spot ratings.
Under the new digital impression definition, each ad opportunity generates an impression for each person passing the digital inventory likely to look at the digital unit. This visibility measure is the same used for all TAB audited inventory, taking into account: size, orientation, and distance to the audience. The speed of the audience throughout the viewable area, known as ‘dwell time’, and the length of each ad on the digital unit derive the number of ad opportunities available to each person passing the digital unit. These changes will result in an increased level of reported impressions. This change will be reflected in the April database release, which currently has a ‘go live’ date of April 13, 2015.
One of the original goals of TAB Out-of-Home Ratings is to help make OOH measurement more comparable with other digital media so that members are properly considered during the planning/buying process. The alignment of the digital impression definition with other digital media helps TAB achieve that goal.