Yes, I’ve been following 538 for a while now. They also grade each pollster.
The point is - 538’s input is a bunch of polls, their output is a prediction. Whether they do the polls or aggregate them is not relevant - they’re analysts whose job is to provide accurate estimates.
You can’t shift the blame on inaccurate underlying polls - Nate has time and again said, they look at many aspects in their estimates. Not just polls.
They look at many aspects at the beginning of the race. By the end these other aspects, the “fundamentals”, are purposefully dialed down to 0 and all that remains is an aggregate of polls. This is based on a theory that polls should be more accurate the closer you get to Election Day because voters have less time people have to change their minds. If those polls are systemically wrong, then there is nothing 538 can do to fix that; it’s a literal garbage in garbage out moment.
Looking at trends, which is easy to do on real clear politics, you could have seen the Senate was going to be extremely close, and the presidency, while not the blowout everyone expected thanks to 538, would still favor Biden. Here's one forecast that was arguably closer than 538: https://www.270towin.com/
The polls did tighten at the end, but you can't just look at a snapshot (even near the end) to account for the trend. In all of these states the polls narrowed in some, but the final results were within MoE:
You can go state by state[1] to see which polls were more/less accurate within MoE compared to the final result and the trends in each state. 538 had a better chance of Biden winning by 400+! EVs [2], than the 306 he's likely to win with. It's this distribution that could have been better at accounting for severe polling errors in some states.
538 did do CYA posts[3], but here while bringing forward the error from 2016 in Ohio seems right, it still projects a win of 335+ EVs. Optimistic for Biden is the kind way of saying what the final 538 projection were, severely more wrong than individual polls is more accurate. If their distribution in [2] was better, I would be more willing to give them a pass.
The point is - 538’s input is a bunch of polls, their output is a prediction. Whether they do the polls or aggregate them is not relevant - they’re analysts whose job is to provide accurate estimates.
You can’t shift the blame on inaccurate underlying polls - Nate has time and again said, they look at many aspects in their estimates. Not just polls.