538 does rank pollsters based on "historical accuracy and methodology"[1], which are then weighted accordingly in their prediction model. And Nate and Elliot M

538 does rank pollsters based on "historical accuracy and methodology"[1], which are then weighted accordingly in their prediction model. And Nate and Elliot Morris (from the economist) have talked about how polling error tends to be normally distributed, so using multiple pollsters with different biases could correct for polling error. Pollsters are picking representative samples and weighting it to reflect the population, so it's not like they're just counting on who picks up their phone (and phone calls aren't the only way to poll anymore anyway). As I recall, in 2016 the pollsters did oversample college-educated white voters, which is what gave Clinton her misleading lead. This apparently has been fixed. There's also the fact that any demographic under or oversampling should be accounted for in the uncertainty range produced by the prediction. I haven't been able to find decent write-ups of this particular part of model forecasting, but from what I've been able to piece together : I believe they quantify the uncertainty of their presidential predictions by building logistic regressions of the output based on highly-correlated predictor data (i.e demographic information, GDP) and then simulating thousands of possible scenarios where demographics trend differently. I don't exactly know how these simulations are set up (I would love to know though). And presumably this is updated in a bayesian matter everytime they get more input data, so the prior probabilities will have an impact on the posterior. If anyone has a different or more detailed idea of how this is done, let me know. In fact, here's the actual code for Elliot Morris' forecasting model: https://github.com/TheEconomist/us-potus-model https://github.com/TheEconomist/us-potus-model if anyone can figure it out better then me. [1] https://projects.fivethirtyeight.com/pollster-ratings/ https://projects.fivethirtyeight.com/pollster-ratings/ [2] https://www.vox.com/21538156/biden-polls-lead-election-trump-2020-2016 https://www.vox.com/21538156/biden-polls-lead-election-trump...