Oh, Alistair's post reminds me of something I read in the book "Thinking fast and slow", where Kahneman proposes using the sum of simple terms that are easy to measure, when trying to predict something. The examples from the book sound exactly like what Alistair described with rugby matches.
If you have a lot of data, you can try to estimate weights for each term. If you have a metric shit ton of data, you can get much fancier with non-linear schemes in (e.g., neural networks). There is a whole subject called Machine Learning about how to make predictions where you have an abundance of data. But Kahneman says that something simple like the sum often works just fine, and I think he might be right.
