Self-selection bias masks the true magnitude of partisan authoritarian differences.

Evidence

We generally assume that the better the return rate, the truer the picture we see. So it would appear that the correlations would have been higher, not lower, if we had heard from everyone. You will find the same trend in nearly all of the subsequent studies, meaning self-selection bias has probably attenuated the true difference between Democrats and Republicans. The real gaps are even bigger. — Bob Altemeyer, The Authoritarian Specter, 3480

Categorization

• XREF: Relevant to survey methodology broadly — response-rate bias in political polling; echoes debates in political science about non-response skewing partisan estimates.