How to Build a Senate Election Model: Step 3

I’m in the middle of a long-term project—I’m building a Senate election model and writing about the process as I go (see previous posts here). At this point I’ve written a lot of the code and I was tempted to devote this update to how I’m aggregating polls, forecasting final vote shares, or thinking about error. But before writing any of those more technical posts, I want to devote some space to a time-honored mathematical tradition: the sanity check.

The sanity check isn’t a specific algorithm or theorem or anything like that—it’s more of an intuitive process that helps you keep your eye on the prize when you’re trying to figure something out.