I have an excel spreadsheet that computes these results to a reasonable accuracy . I first input demographic data provided by the ACS , combined with turnout data by racial group provided by NYT Upshot exit polls by state to determine the electorate composition of a county . Next , I calculate the support of various nonWhite groups by county . Excepting places like Indian reservations or known Demographic outliers among the nonWhite vote , like Cubans in Miami where I directly look at precincts to get an idea I calculate this based on a formula in relation to partisan support . Having looked at several hundred data points in the form of precincts , I ' ve been able to calculate how much , on average , the minority vote diverges from the statewide average based on the overall partisan lean of the district . As it turns out , the minority vote is more Democratic than the statewide average in democratic leaning areas which shouldn ' t really come as a surprise . Through the excel spreadsheet , I then calculate the partisan spread between the county and statewide results to determine how much more Democratic the nonWhite vote is determined by a formula compared to the statewide support determined by exit polls and the NYT upshot analysis . I then resum the minority vote by county taking into account turnout differentials by county and the share of the minority vote by county to make sure they match the statewide totals . If they don ' t match , I then apply a weight to all of the counties equally statewide to correct it so that the sum of the counties matches the exit poll results . At this point , if you know the margin of the nonWhite vote , it ' s simple arithmetic to calculate how the White vote went .