For decades, the gross rating point (GRP) metric has been used in television advertising to calculate campaign exposure with respect to reach and frequency against a target demographic audience. GRPs are now available for digital video advertising through Nielsen online campaign ratings (OCR). The ad industry had been pushing for the ability to compare TV buys to digital video -- and it's finally arrived, opening the door to a new kind of conversation between TV and digital buyers. Digital buyers need to prepare for this before it happens. They have an opportunity to evaluate digital video advertising through the lens of a TV buyer before it's forced on them. If there's ever a time to be proactive about something, it's now. Here's how a digital buyer can be proactive with respect to GRP measurement: First, recognize that the only impressions that matter to a TV buyer are those that reach the target demographic. For example, if the on-target demo is men ages 18-34, any impressions that reach anyone outside this demo will be considered wasted impressions. So, evaluating a digital buy on TV standards means considering off-target impressions as waste. Second, develop an in-depth understanding of how well the digital video impressions bought for a campaign match the campaign's on-target demo. It would be easy here to assume that, thanks to audience buying, a digital video buy would have very low levels of off-target waste. However, when Nielsen OCR is used to evaluate the on-target percent of a digital buy, it's using different data than any third-party demographic data used for audience buying today. Digital buyers will want to understand the discrepancies between the targeting they've been using and the on-target percent evaluation that's built into OCR. For example, suppose a CPG advertiser wants to reach men ages 18-34 with a 30-second commercial spot run across a TV and digital video buy. In digital video, they run 50% of impressions through site targeting among the likes of sports sites with a strong appeal to their demographic, and the other 50% of impressions through audience targeting using a DSP and third-party data provider. The interesting part about this is that the advertiser’s TV buy also has a measure of wasted impressions since not all viewers fall within the desired target. The CPG advertiser then uses OCR to compare GRPs in television and digital. And the digital buyer is also looking at the percent of on-target impressions delivered via their digital buy to identify potential wasted impressions and optimize the buy for the highest on-target percentage. Here's where the discrepancies begin to surface. The on-target results for the site and audience targeting may be totally different from what the advertiser, publisher or data-provider expected. Nielsen may report that only 60% of site-targeted impressions were on-target, or that only 50% of audience-targeted impressions were on-target. To truly be prepared for a conversation with the TV buyer, digital buyers need to judge all the ways they buy digital video with respect to on-target percent. They should ask: