> AFAICT the polls had a systemic error AND the 538 models included the possibility of a systemic error.
Well, 538 model took into account historical evidence that election differences from polling averages between states are strongly correlated rather than independent; arguably, that's an effect that exists in part because such deviations are in part due to systemic errors (though the particular systemic errors may differ from cycle to cycle) in the polling, rather than pure sampling error.
Well, 538 model took into account historical evidence that election differences from polling averages between states are strongly correlated rather than independent; arguably, that's an effect that exists in part because such deviations are in part due to systemic errors (though the particular systemic errors may differ from cycle to cycle) in the polling, rather than pure sampling error.