- A statistical model for probability of default - A rule-based model implementing a policy, taking into account the probability and other signals not captured in the probability
Not everything could be incorporated into the probability, so this was a nice way of having a hand-crafted decision tree. Also, we could tune it eventually, much easier than training and validating a new statistical model.
You bring up something awesome about CLIPS: it's easy to tailor it to your needs. Once you have your CLIPS code, you can trim out the parts you don't need using compiler flags. Once you have a compiled `clips` binary with only the constructs you need (defrules and deffacts, maybe?), you can execute it, load your rules/facts into the engine, and then generate C code for your specific rules engine. This compiles into an even smaller/faster binary. You can do all of this from within CLIPS proper. Check out the Advanced Progamming Guide section 11: Creating a CLIPS Run-time Program https://www.clipsrules.net/documentation/v641/apg641.pdf