> due to the fact that republicans are more avid betters than democrats.
not sure where this is coming from, but I did not study how large and predictive betting markets are. A more proven way would be to look at stock market. There are known industries that will benefit from one of the candidates (T – oil, K – solar, etc). So, looking at their stocks would show you the odds. It does not matter who trades these – there is a lot of money here and a lot of analysis goes into making those bets. I am guessing that election betters simply use stock market analysis to bet. There are some articles that look at that.
Caveat: stock market failed in Trump/Hillary election. Yes, Hillary had 70% chance, which is not that high, but lazy brokers relied on the idea that she’ll win and they did not even bother to analyze Trump’s effect on economy. What happened (my recollection): in the middle of the election night when adds switched to T, stock market futures went down – because everyone wanted to sell pro-H stocks. It took several hours to do analysis of which stocks are pro-T and then futures went up (for several years). Given that failure is still remembered, surely nobody will make same mistake this time around.