I developed a predictive model for the Democratic primaries that was designed to have the following features:
1) It does not rely on polling;
2) It does use exit polling and other information to set certain parameters;
3) It mainly uses prior primary or caucus results to predict the future, and thus assumes that the status quo is the best indicator.
4) It calculates likely voting patterns based on ethnicity (White, African American, Hispanic), and using likely Democratic party distribution among these groups to predict each contest’s outcome.
That method outperformed most other predictions for Super Tuesday and accurately predicted who would win in the four contests held over the last weekend. However, in states that Sanders won last weekend, and in at least two of the Super Tuesday results, the method underestimated how well Sanders would do. Notably, the numbers used to predict those primaries accurately predicted how Clinton would do in Louisiana, and generally.
In other words, mostly, where Clinton won, the model was accurate, but where Sanders won, Sanders did better than expected, not counting “favorite son” states where he did even better.
The most likely reason for the difference between prediction and reality over last weekend, since this is a status quo poll, is a change in voting patterns. In other words, it is possible that Sanders is picking up some momentum. That does not explain why the largest of the primaries, Louisiana, fit the predicted pattern while the others do not.
A second possibility is that Sanders outperforms expectations in caucus states. That seems almost certainly a factor, which I can not explain.
A third possibility is crossover voting or independents favoring Sanders in some, but not all, states. If Republicans are voting in the Democratic contest, or independents are showing up at the Democratic events, specifically because they want to vote for Sanders, that could explain a localized Sanders surge. This does not do well explaining last weekend’s results, because Sanders won in closed caucuses. But, it could explain some earlier results, such as Massachusetts and Minnesota. I know for a fact that some Republicans and a lot of “independents” (as in, “I never did this before, see how independent I am”) voters showed up in the Minnesota caucus. The question remains, of course, where were these voters in Louisiana?
One explanation for this may be that the indies and centrists in more conservative southern states, which also happen to have a lot of pro-Clinton African American voters, are mostly registered Republicans or chose to participate in the Republican rather than Democratic process, while similar voters in less conservative or liberal states were already more likely to be Democrats or to at least participate this year in the Democratic primaries or caucuses. Differences in voter turnout across states seem to conform to this pattern.
Last weekend barely added enough data to consider revising the model. Assuming that the status quo method still works, but with somewhat adjusted numbers to match Sanders wins so far, and combining projections into the future with primary results so far, this model now puts Sanders on top at the very end of the primary process, like this:
I quickly add that I don’t have a lot more confidence in this projection than the previously developed projection that has Clinton winning. But this new projection is important because it accounts for what might be recent changes in how people are voting.
Michigan’s primary, to be held tomorrow, is important. Michigan is relatively diverse, and is northern (less conservative, etc.). The modified model predicts that Sanders will swamp Clinton in Michigan, picking up over 70 delegates to Clinton’s low-fifties. In contrast, the previous iteration of the model predicts that Clinton will win with about 66 delegates and Sanders will pick up a healthy 60 or so.
Michigan’s contest is a primary, not a caucus, but it is open, so cross-party activity is possible.
Michigan will be a test between the two models, the older one that ultimately favored Clinton, and the revised (but far less certain) one that suggests that Sanders could eek out a victory.
Michigan plus last weekend’s contests combined will give me enough data to produce The Model of Models which will accurately predict the outcome of primaries coming up in Florida, Illinois, Missouri, North Carolina and Ohio. Or not. We’ll see. It is possible that I’ll add an element to the model, using one set of assumptions for red states, another set for blue states.
One week after Michigan, Son of Super Tuesday happens. If either one of the candidates is very strong on that day, that may finish off the other candidate. The actual number of committed delegates is not too different between the two candidates, and the so-called “Super Delegates” will probably be obligated to go with whoever enters the Convention with the most delegates.