Online political advertising is booming. But how much does scholarship know? This gap exists because most research uses only televised ads.

New data offers a solution. Researchers now have access to the Facebook Ad Library API and television data from the Wesleyan Media Project.

Using this combined evidence, we looked at candidates in 2018 elections across all levels: federal, statewide, state legislative.

We found something surprising:

* Who Advertises: More candidates use Facebook ads than TV ads. Especially for down-ballot races.

* Strategic Differences: Candidates who advertise online do so differently depending on the platform.

* Their Facebook ads start earlier in campaigns.

* They are less negative and more partisan.

These findings show that digital advertising is changing political communication, opening up new ways to reach voters.