How the Map and Polling Averages are Determined
The Polling Averages:
There are slight changes here; you can see those in the 21 August update for now,
I take polling data from Electoral-Vote.com which avoids using partisan polls.
To get each state’s polling average we take the arithmetic mean of all the polls released in the previous ten days. When there are no polls within the 10-day window, the most recent poll is used.
The polling averages were fed into a US Presidential Election Calculator; an earlier version of which can be found at MapleSoft Application Center.
The calculator runs a large number of simulated elections. The probability of each candidate winning is estimated by the percentage of the simulations won by each candidate.
The Map:
The colors on the map are determined by The polling estimate rather than by the probability that a candidate will win a state.
In each state, we use the polling estimate to find the conditional probability that an individual voter would choose either the Democrat or the Republican assuming they are voting for one of the major party candidates. Thus, to find, for example, the probability that a voter would choose the Democratic candidate, assuming they are voting for a major party nominee, we would calculate the following.
P(D|D or R) means “the probability a voter will vote for the democratic candidate assuming they voted for either the Democrat or the Republican.” If a third-party candidate were to poll well enough to potentially win a state we would need to revise our model.
The colors on the map are determined as follows:
| Color | Criteria | |
|---|---|---|
| Solidly Democratic | Dark Blue | 100% > P(D|D or R) > 55% |
| Leaning Democratic | Blue | 55% > P(D|D or R) > 52% |
| Barely Democratic | Light Blue | 52% > P(D|D or R) > 51% |
| Toss-Up | Taupe | 51% > P(D|D or R) > 49% |
| Barely Republican | Pink | 51% < P(R|D or R) < 52% |
| Leaning Republican | Red | 52% < P(R|D or R) < 55% |
| Solidly Republican | Dark Red | 55% < P(R|D or R) < 100% |
If a candidate is polling at 55%, the probability that they will win the state is actually quite a bit better than that.
Comics, the Universe, and Everything 