Upsets by the thriftier of the top two candidates are rare. According to data from OpenSecrets.org, they claim victory in only 1 in 10 of the 468 Congressional races in a good year, but most of the time it’s closer to only 1 in 20. And a Congressional candidate that spends no money on their election at all never wins.
It’s easy to see why spending no money is a bad thing, especially if you have no name recognition to start, and one might argue that the raising and spending of money in an election is really what a good political race is all about, that when the candidates debate over ideas for policy and interact with the public, they’re fighting for dollars to build excitement and momentum for their campaign as much as they are fighting for votes on election day. The problem with this rosy model is that Congressional races aren’t really competitive, with the winner most often completely crushing the opposing candidate with a torrent of campaign spending.
Splitting winner spending into categories, one can see that well over a third of winners, more than a half in most election cycles, spend more than 20 times what the next most popular candidate does, and the winner spending more than 10 times their opponent happens half the time or more in any given year, two-thirds of the time in 2016. Winners spending only twice as much as their opponents or less make up a relatively small portion of races.