stan-dev / stan-dev/loo

Handle frequency weights with loo

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Dominant language
R
Stars
157
Forks
38
Avg merge
4d 16h
Merged PRs (30d)
2

Description

In some cases models are specified ("compressed") with frequency weights to speed up the fitting, however, this doesn't work well with loo as the Pareto k's indicates that all observations are heavily influencing the posterior, which of course it true on the aggregated level, but may not be true in the disaggregated level. Some kind of adjustment (I suppose disaggregation of the log-likelihood is a part of it) would be needed for such a case.

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Research direction

No files, tests, or entry points are named. Start by reviewing how loo handles frequency-weighted or compressed models and how log-likelihood observations are represented. Define the required adjustment for disaggregated observations and validate that Pareto k diagnostics reflect the intended observation level.

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Assessment

Tech stack
r
Domain
data
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
20/100

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