What data exists to support the claim that ranked choice voting increases participation in the democratic process?

Although ranked choice voting is still relatively new, there is evidence that ranked choice voting can encourage higher participation rates.

For the 2011 Mayoral race in Portland, they were only expecting a 25% voter turnout because it was an off-year election.  However, they were shocked when more than 40% of voters turned out. Other cities have seen comparable results.