How the wedge is computed
Market prices are from Polymarket, fetched daily (Kalshi's prices are also available as a toggle). The poll side is the RealClearPolling average for each race, refreshed weekly and converted to a win probability with a simple polling-error model. Senate control uses Decision Desk HQ's forecast instead, as there is no margin to convert. Wedge = market − polls, in percentage points. Every row is read from the Democratic side, so a positive wedge means the money leans more Democratic than the polls and a negative one more Republican.
The size of the wedge is the hope (someone is betting the polls are wrong). The sign is whose hope it is. Wedges near 0% or 100% should be read loosely, since markets rarely price above 90¢ or below 10¢.
Market history before launch (Oct 9) is backfilled from the prediction markets from mid-August. The poll line before launch is a 28-day rolling average of the individual RCP-listed polls (using at least three polls and not RCP's own average), shown as a dashed line. Full details can be found in the methods & assumptions. NOTE: this is a data project by Daniel A. N. Goldstein, not investment advice. Code & data on GitHub.