PIRG and National Voting Institute has released a report showing there is no evidence that campaign contribution limits provide an advantage to incumbents. From BNA: A statement releasing the new study said it showed that contribution limits do not increase the contribution bias in favor of incumbents or increase the differences in fund-raising among gubernatorial candidates in general. Contribution limits benefit challengers by decreasing the ratio of contributions made to incumbents versus challengers by "policy-oriented" contributors, including corporations, labor unions, and political action committees (PACs), the study found. "This study confirms what common sense and previous research strongly suggest--leveling the playing field through reforms such as contribution limits is not bad for challengers," said one of the report's authors, State PIRGs Democracy Advocate Adam Lioz.