The current make up of the Senate is 53 Republicans and 47 Democrats, counting the 2 independents as Democrats. Only 16 states are in play in having market probabilities on the Predictit website less than 90 percent and greater than 10 percent. The 16 states ranked by the market probabilities from Predictit for the Democratic candidate are:

If the Democrats win North Carolina and all the states above it, they will have 51 seats, counting the 2 independents as Democrats. If they win Maine and all the states above it but lose North Carolina, they will have 50 seats. They will still control the Senate if they win the White House. According to the ranking assumption, the Predictit market probablility that they control the Senate is thus 77 percent (the probablity they win Maine) if they win the White House and 58 percent (the probablility they win North Carolina) if they don't. If we use the Predictit market-based probabilty of 66 percent that the Democrats win the presidential electon, then the ranking assumption probability that the Democrats control the Senate is 0.66x77 + 0.34x58, which is 70.5 percent. This is somewhat higher than the Predictit market-based probability of the Democrats controlling the Senate of 66 percent. So the market is not quite using the ranking asssumption.

Data collected from Predictit on October 20, 2020

The current make up of the Senate is 53 Republicans and 47 Democrats, counting the 2 independents as Democrats. Only 16 states are in play in having market probabilities on the Predictit website less than 90 percent and greater than 10 percent. The 16 states ranked by the market probabilities from Predictit for the Democratic candidate are:

If the Democrats win Iowa and all the states above it, they will have 51 seats, counting the 2 independents as Democrats, and assuming that they lose Alabama. If they win North Carolina and all the states above it but lose Iowa, they will have 50 seats. They will still control the Senate if they win the White House. According to the ranking assumption, the Predictit market probablility that they control the Senate is thus 60 percent (the probablity they win North Carolina) if they win the White House and also 60 percent (the probablility they win Iowa) if they don't. If we use the Predictit market-based probabilty of 65 percent that the Democrats win the presidential electon, then the ranking assumption probability that the Democrats control the Senate is 0.65x60 + 0.35x60, which is 60 percent. This is slightly smaller than the Predictit market-based probability of the Democrats controlling the Senate of 65 percent. So the market is not quite using the ranking asssumption.