Predictit is a real-money prediction market, registered as a research project run by Victoria University of Wellington, New Zealand. Predictit has one market at which participate trade on the popular vote margins in the 2020 U.S. presidential election.

PollyVote translates the predictions into an overall vote-share market by translating by

  1. taking the mid point for the margins of each contract. For example,
    • “GOP by 1.5%-3.0%” => +2.25
    • “DEM by 4.5%-6.0%” => -5.25
  2. calculating the margin across contracts as a weighted average, weighted by the last closing price
  3. converting the margin to Trump’s two-party vote share as follows: VS(Trump) = (Margin+100)/2