Last year, Google launched its Reach Planner tool which provides estimates for YouTube ad campaign reach and performance based on a range of metrics and inputs.

Now Google's looking to improve its comparison tools by adding in TV reach data from Nielsen, in order to provide insight into how ad spend on both TV and YouTube can impact campaign reach.
The additional data will help brands cover potential gaps in their targeting - as explained by Google:
"With audiences shifting to digital, it’s important to plan across channels. According to Nielsen, there are 31% fewer available weekly 18-49 GRPs across broadcast and cable television compared to just five years ago."

Now, with comparative TV and YouTube data on one screen, advertisers will be able to identify optimal targeting and reach options to achieve their desired goals.
Obviously not all advertisers will benefit from this, as not all are running TV ads, but for those who are using online and traditional TV campaigns, the comparative data could provide significant insight, and help to optimize reach.
Nielsen TV data is now available to all users of Reach Planner in the US, and will be rolled out to other regions next year.