If you withhold a small amount of data, or even retrain on a sample of your training data, then isotonicregression is good to solve many calibration problems.
I also agree with your intuition that if your output is censored at 0, with a large mass there, it's good to create two models, one for likelihood of zero karma, and another expected karma, conditional on it being non-zero.
I hadn't heard of isotonicregression before but I like it!
> it's good to create two models, one for likelihood of zero karma, and another expected karma, conditional on it being non-zero.
Another way to do this is to keep a single model but have it predict two outputs: (1) likelihood of zero karma, and (2) expected karma if non-zero. This would require writing a custom loss function which sounds intimidating but actually isn't too bad.
If I were actually putting a model like this into production at HN I'd likely try modeling the problem in that way.
Did you dictate this? It looks like you typo'd/brain I'd "centered" into "censored", but even allowing for phonetic mistakes (of which I make many) and predictive text flubs, I still can't understand how this happened.
I was thinking of censoring, maybe I should have said another word like floored.
The reason I think of this as censoring is that there are are some classical statistical models that model a distribution with a large mass at a minimum threshold, e.g. "tobit" censored regression.
Thanks for the explanation. I never paid much attention in my stats lectures so I deserve to have missed out on that term-of-art. I think the physics lingo would be to call it "capped" or "bounded" or "constrained".
https://scikit-learn.org/dev/modules/generated/sklearn.isoto...
I also agree with your intuition that if your output is censored at 0, with a large mass there, it's good to create two models, one for likelihood of zero karma, and another expected karma, conditional on it being non-zero.