Does the participation bias explanation assume that fraud is unthinkable?
I will present several lines of argument that participation bias accounts for much of the exit poll discrepancy, and that fraud does not. (By the way, concluding that fraud doesn’t account for the exit poll results isn’t the same as ruling out fraud generally.) The pollsters had several good reasons to suspect from the outset that participation bias was important. First of all, non-response bias — and other forms of non-sampling error — are ubiquitous concerns in survey research. Survey researchers do not assume that their data are accurate within the computed “margin of error,” because they are well aware of everything that can go wrong. Second, the national exit polls’ history of overstating the Democratic vote share in precincts, as described in point 3.2, gives additional reason to consider participation bias likely. Also, we know that the exit pollsters tested a specific hypothesis about massive fraud: that millions of votes were stolen on electronic voting equipment (Direct Rec
