What progress if any has been made during the switch to California’s top-two system for primaries? From Ballot Access News:

Forbes has this commentary by David Davenport, on California’s top-two system and the 2016 U.S. Senate race. The title is “Beware Election Reforms that Eliminate Voter Choice.” He summarizes political science research that shows the California top-two system has not changed who gets elected, or how they behave once in office. Then he points out that a California Poll finding that half of all Republicans say they will leave U.S. Senate blank this year when they vote in November.

From the Forbes article:

It turns out that the reformers were wrong and wronger. Early research indicates that there has not really been much change at all in favor of more moderate officeholders in California since the new primary system was implemented. A recent study published in the California Journal of Politics and Policy at U.C. Berkeley reviewed several papers on the subject and concluded that the desired outcomes of more competitive contests and more ideologically moderate elected officials “have mostly not taken place.”

Another study, published in Legislative Studies Quarterly in the spring, concluded that voters know how to choose ideologically between Democrats and Republicans, but “appear to know so little about the candidates’ positions that, even if they wanted to, they could not intentionally cast a ballot for…moderate candidates.”