Via John Sides, along comes political scientist Dan Hopkins with some empirical research into the "Wilder effect" question (PDF, the phenomena whereby black candidates get a smaller share of the vote than public polling would have predicted.
Titled "No More Wilder Eﬀect, Never a Whitman Eﬀect: When and Why Polls Mislead about Black and Female Candidates," the paper concludes that there really was a Wilder effect in the early 1990s but there isn't one any more. Here's the abstract:
Using new data from 133 gubernatorial and Senate elections from 1989 to 2006, this paper presents the ﬁrst large-sample test of the Wilder eﬀect. It demonstrates a signiﬁcant Wilder eﬀect only through the early 1990s, when Wilder himself was Governor of Virginia. Although the same mechanisms could impact female candidates, this paper ﬁnds no such eﬀect at any point in time. It also shows how polls’ over-estimation of front-runners’ support can exaggerate estimates of the Wilder eﬀect. Together, these results accord with theories emphasizing how short-term changes in the political context inﬂuence the role of race in statewide elections. The Wilder eﬀect is the product of racial attitudes in speciﬁc political contexts, not a more general response to under-represented groups.
Good to know.