Nielsen said it reached an agreement to use data from Comcast’s set-top boxes in its local TV ratings service.

At a time when big data is becoming a bigger part of audience measurement, Nielsen now has access to viewing information from four of the major cable and satellite providers. More granular data could help transform how local advertising is bought and sold.

“Our enhanced Local TV measurement strategy combines the best elements from Nielsen’s high-quality panels with set-top box data from Comcast and other providers in an anonymous way,” said Megan Clarken, Global President of Watch at Nielsen. “We are continuously innovating our local measurement solutions and leveraging all data sources to deliver a comprehensive service that offers true local market insights and showcases the power of local television. We are pleased to add Comcast to our list of local set-top box data providers.”

In 2018, Nielsen will begin to incorporate anonymized data from Comcast homes along with set-top box data from other providers and Nielsen’s local meters into local TV ratings. The data will be used to report audience viewing trends on an aggregated basis.

“Comcast is committed to enabling more effective and efficient television measurement for the benefit of the entire industry,” said Marcien Jenckes, President, Advertising, Comcast Cable. “This agreement with Nielsen underscores the importance of local television measurement and will have a positive impact on the quality of local ratings.”