Much more money flows into races that the Cook Political Report rates as a toss-up or moves closer to toss-up territory — especially on the House side, according to exclusive data from Advertising Analytics, a data firm specializing in media ad spending and real time ad detection that specializes in politics.

Why it matters: In addition to traditional gurus like Charlie Cook, new factors in the internet era — virality, digital fundraising operations and activist digital media outlets — are increasingly affecting how money moves in politics.

The details: In 2018, 40% of all spending on House races went to races that Cook labeled a "toss-up." By comparison, only 20% went to races that were ranked solidly Republican or Democrat.

In 2018, a whopping 80% of all spending on Senate races went to races that Cook labeled a "toss-up." By comparison, only 3% went to races that were solidly Republican or Democrat.

Race ratings are often reinforced by positive media coverage and polling, as well as additional factors like FEC reports, ads and spending data, district and state demographics, past election results and interviews. The closer a race the Cook Political Report foresees as a result of those factors, the more money one can be expect will flow into that race.

The same thing goes for flipping Congressional chambers on a bigger scale. Because polling and ratings forecasted that Democrats were expected to flip the House, Democrats outspent Republicans $555 million to $403 million to ensure that outcome.

By comparison, both parties spent an estimated $461 million on Senate races.

The big picture: Charlie Cook, editor and publisher of The Cook Political Report, notes that Washington analysts' fundraising influence, while meaningful, has diminished over the past two decades.

"Frankly, I think Washington-based political newsletters have less influence on campaign fundraising than they did 20 years ago," Cook tells Axios.

"More money is coming from the man or woman sitting at home on their laptop watching an MJ Hegar or Beto O'Rourke (Senate) video that has gone viral, and then going on ActBlue and sending $10.... That really mounts up."

Between the lines: Data from Advertising Analytics also shows that candidate spending over the past three cycles is increasing at a much higher rate than spending from issue groups.

Since 2014, super PACS (political action committees) and party committees have increased ad spending by 65%. However, since 2014, Democratic candidates have increased ad spending 170%, far outpacing the trend.

Go deeper: