37% don’t regularly watch MSNBC or Fox News

The first two debates among the Democratic candidates for president drew more viewers than expected, but an analysis by Samba TV found that few of those viewers were light TV viewers.

Looking at both debates, Samba’s data shows that 48.2% of those who tuned in are classified as heavy TV viewers, with another 43.2% classified as mediumTV viewers. Less than 14% of the viewers of either of the debates were classified as light TV viewers.

People who watched the debates were most likely watching NBC before the debates--Ellen’s Game of Games before the first debate and The Wall before the second debates. The second biggest block of viewers left Fox News Channel to watch the Democrats debate and the third biggest block came from pre-debate programming on MSNBC.

After the debates, about a million viewers stuck around on MSNBC for post-debate analysis on each night. About 400,000 stayed with NBC for the Tonight Show. Nearly as many viewers flipped the channel to Fox News to get that network’s take on the debate. Those channels were followed by CBS’s Late Show and CNN in drawing post-debate viewers, Samba found.

Samba said about 24% of the people watching the debates were MSNBC viewers, which makes them most likely Democrats, while 18.5% were Fox News viewers, or likely leaning Republican. 37% of viewers were neither MSNBC or Fox News viewers while 5.8% tend to watch both.

“I'm wondering if they'll be a big difference in the skew for the next set of debates, which are on CNN,” said Katherine Sicienski, senior research manager at Samba. “Because these aired on NBC as well there's a good chance you're getting a lot more general viewers and I'm wondering if we'll see that shift for heavy news viewers when we're talking about debates that are on CNN. That'll be an interesting thing to keep an eye on.”

Tune in was highest for both debates in Washington D.C., and New York. Boston and Miami were also big viewers of both debates. Among the top 25 markets Samba looked at, the lowest tune in was registered in Charlotte, Atlanta and Detroit.

“In some of the cities, they turned out to follow their candidate,” said Jeffrey Silverman, director of data science and analytics at Samba, pointing to Boston with Elizabeth Warren and Sacramento and San Francisco with Kamala Harris.

“I think the other thing to look at is the swing states. Tampa and Orlando were sort of in the middle and Cleveland was kind of low,” Silverman said. “People in swing states may not be engaged yet. They may be waiting for the candidates to swing through their states.”

From a demographic point of view higher income households over indexed, while low income households under indexed.

White households also over indexed while African American and Hispanic viewers were less likely to tune in.

"That means that if Kamala Harris’ strategy was to cut into the African-American support for Joe Biden, it might not have had much of an effect," Sicienski said.