House‘s current eighth season ratings have remained solid, particularly for a drama airing at 8 p.m. The Monday night show averaged 9.8 million viewers and a 3.9 rating in the adult demo this season through early January when including seven days of DVR playback.Since when should advertisers consider DVR playback? The DVR portion of the of audience adds only 16% to raw in-time viewing Gross Rating Points (GRP) according to this Nielsen study of DVR usage (as quoted in the New York Times). Let's say for the sake of argument that this particular show, like others, has 40% of the audience using a DVR. If that's the case, the real viewership was:
9.8 million * (1 - 40%) = 5.9 million * (1 + 16%) = 6.8 million
If (as an advertising buyer) you based your effective cost per thousand viewers (CPM) on the 9.8 million, you were over-paying by over 44%.
The misrepresentation probably stems from the network's presentation of their own overblown statistics. I have learned over the years to be highly skeptical of any vendor's own statistics, and in my own work for Vocollect, Inc. I try hard to provide our own customers an independent validation of statistics we quote on our truly superior products. The article mentioned above offers just one more reminder to smart market research analysts and marketing data consumers: examine the sources and rely on your own brain when using external data.