This will use the final polling average from 

RealClearPolitics for battleground states 

and compare them to the actual Democratic vs Republican spread when the voting totals are finalized.

Resolution will be a percentage based on the following formula using the Republican vs Democratic spread:

The goal of this market is for traders to anticipate and model potential demographic overlap and provide a market idea of which states should vary together.

If Battleground states are added later (or are consistently aggregated in a similar way by RCP) I might add them. If Battleground states drop off (or see a significant reduction in polling) then I reserve the right to N/A all correlations for a state, although ideally I would find a different source for polling aggregation before that.

For pure Yes/No same party winners of states, I've also created this market: