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Scenario: I develop a model which forecasts the likely sales success of a particular enquiry based on outcomes of past similar enquiries. I then assign this likelihood score to new enquiries when they come in. The sales team use this to optimise their behaviour, giving more focus to the higher scoring enquiries, and thus imrpoving their outcomes.

When newer records are incorproated into the model, they are skewed, due to the bias introduced from having the additional score information. Over time, this causes the dataset to polarise, with higher scoring items getting higher, and lower scoring items get lower. Eventually it renders the model unusable, as more and more records fail to make the grade and end up falling to the low end.

a) does this effect have a proper name?

Edit: I believe this is a Degenerate Feedback Loop.

b) what are the standard approaches for dealing with it?

Ian
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  • If the model becomes unusable after a while, maybe the problem lies with the strategy itself. If you try to optimize one specific thing, and when this thing gets optimized it is considered a problem, maybe you shouldn't have tried to optimize this at all. – liakoyras Dec 12 '22 at 13:00
  • Perhaps I need to restate. – Ian Dec 15 '22 at 10:12
  • Perhaps I need to restate. Yes - the goal is to optimise, that's a good thing. However, over time the domain behaviour changes. What I want to be able to do is differentiate between changes due to the optimisations and "natural" changes in the underlying environment, to ensure the model doesn't become a "mis-optimisation" over time. I'd considered something like adding a small number of unoptimised/false results so I'd have a control set, but thought there must be some standard practices out there? It maybe I just don't know the terminiology to search for? – Ian Dec 15 '22 at 10:19
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    After a bit more reading, I believe what I'm describing is a degenerate feedback loop. This seems to be a pretty good fit for my issue: https://huyenchip.com/2022/02/07/data-distribution-shifts-and-monitoring.html - it also sounds like I may have assumed too much in expecting a standard solution. – Ian Dec 15 '22 at 11:03

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