For the first time since 538 published our presidential election forecast for Vice President Kamala Harris and former President Donald Trump, Trump has taken the lead (if a very small one) over Harris. As of 3 p.m. Eastern on Oct. 18, our model gives Trump a 52-in-100 chance of winning the majority of Electoral College votes. The model gives Harris a 48-in-100 chance.
Yes, but their “house effects” (how much their polls lean Republican or Democrat) are accounted for by every worthwhile polling aggregator.
If they were just taking the averages and spitting out results, well, it’d be nonsensical. You could maybe argue that Republican pollsters have tweaked their systems to be more trumpy but that’d be a pretty huge red flag and mark you as completely non trustworthy in your professional field.
You can read Silver’s more in depth and interesting explanation here:
https://www.natesilver.net/p/are-republican-pollsters-flooding