Some improvements from Andrew Ferguson: The update date/time above now links to the history graph, and the Obama/Romney numbers link to the map.&...
It’s alive! Election tracking 2020, Part 3: The Presidency
Detailed explanation to come. Basically, it’s the same as the 2016 calculation – a simple snapshot of polls to give a sharp picture of where the race is on any single day, to allow optimization of resource allocation.
The November prediction (red zone, one-sigma; yellow zone, two-sigma or 95% confidence band) comes from estimating the likely amount of drift between now and Election Day. The major change is putting a higher floor on the minimum level of uncertainty in the home stretch. Increasing the floor (to 2 percentage points) prevents overconfidence in the home stretch, while retaining the sharp time resolution that we get from day to day from now until then.
Contributors to this feature: Lucas Manning, Ben Deverett. The code is at https://github.com/Princeton-Election-Consortium/data-backend. Outputs: tables and charts.