Thanks again for taking the time to produce a long thoughtful response! I’m enjoying this conversation, and happy holidays to you too!
It’s to make sure the GRW “walks” towards its priors instead of away from it when one doesn’t have much data. And the nice thing is that the prior is actually the result of another model, called “the fundamentals” model.
Ok this makes a lot of sense. Seems so simple now that you explain it haha. Thanks!
When that happens, the beauty of this model is that it reverts to the fundamentals forecast (which doesn’t contain polls, only socio-econ variables available well in advance of the election) to still be able to make a forecast.
In this case though shouldn’t each state then walk toward the dashed line since thats the Time-for-Change model? Florida does but Indiana drifts away from it. Indiana also far less polls than Florida so I would expect the model to be more heavily leaning towards the Time-for-Change outputs. Furthermore, with 2 months before the election Indiana starts at the Time-for-Change result and forecasts a drift away from it.
Maybe I’m too focused on that single figure but I just can’t square that result with my understanding of the model.