A key project for Data for Progress is deepening the understanding of how geography interacts with politics. Geography is recognized as an important factor in electoral politics, but is often ignored in opinion polling which typically only estimate national popular support. State level polling is very expensive and rarely performed, particularly for public consumption. Data for Progress uses state of the art statistical methods to estimate state level opinion from national polls, which is cheap enough to make state level estimates routine.
We’re testing out a new way to summarize how opinions are distributed through the states by estimating the support in the median state. Half of states will have higher support than the median while the other half will be lower. That means that if there is majority support for a policy in the median state, then there is majority support in a majority of states. This is a useful way to determine how viable a policy is in the Senate.
Comparing the national popular support to the support in the median state is a simple way to determine whether a policy is helped or hindered by geography. If the national average is bigger than the median, that means that support for a policy is more concentrated in a smaller number of states, as opposed to being spread out evenly across all states. For a recent example of this dynamic, consider the 2016 election, where Hillary Clinton won the national popular vote but lost a majority of states and the electoral college. Based on our analysis of polling to provided us by the Center for American Progress (see their findings here), Trump’s geographic advantage still persists a year after his inauguration. Analyzing Trump's approval in January 2018 shows us that while Trump has low national approval, his support in the median state exceeds his national support by about 3 percentage points, which is the same boost he got from geography on election day 2016.
Understanding political geography for national electoral politics is just the beginning. Our goal is the use these methods to help advance the most progressive agenda that is feasible at every level of government.