Two economics professors at Gonzaga University in Spokane have published “The Effect of the Top Two Primary on the Number of Primary Candidates.” It will appear in a future issue of the Social Science Quarterly, journal of the Southwestern Social Science Association. It is already available on-line, but it requires payment. See here for the link to the article on the Wiley Online Library.
The article is by John H. Beck and Kevin E. Henrickson. Comparing the Washington state classic open primaries of 2004 and 2006 with the top-two primaries of 2008 and 2010, the article conclude that the top-two system appears to have caused a reduction in the number of Democrats who run for the Washington state legislature. Each year, there are 123 or 124 regularly-scheduled legislative races in Washington state, and the study uses complex statistical analysis to show that, in the average election year under top-two, 18 to 19 fewer Democrats run for the legislature than if the top-two system did not exist. The evidence in the article is entirely statistical, except for one anecdote, in which the chair of the Democratic Party is quoted as saying, “I, as party chair, have to go and talk people into not participating, and I think that’s really unfortunate.”
The reason party leaders discourage party members from running is that if a major party has too many candidates for a single seat, the party is in some danger that no member will qualify for the November ballot. The article thus provides evidence for the point that top-two open primary systems reduce voter choice in primaries, and enhance the power of “party bosses”. Thanks to Mark Rogalski for news of the article.