Ratio With Shrinkage

Performs empirical bayesian estimation with shrinkage towards a beta prior. Given a dataset with a numerator and a denominator, will calculate the raw ratio as numerator / denom, as well as provide an adjusted ratio that shrinks the ratio towards the observed beta prior.

This is a simplified version that establishes the priors directly from the data given a min_cutoff count of observations.

NOTE: your data should already be aggregated before performing this operation.

Parameters

Name	Type	Description	Is Optional
numerator	column	A column that is pre-aggregated to contain the count of positive cases
denom	column	A column that is pre-aggregated to contain the count of ALL cases
min_cutoff	int	Enter a minimum value to limit the denominator when creating the prior estimates. Example: if estimating a batter's hitting percentage, entering 500 would limit the estimation of the priors to be only for batters with over 500 at-bats.

Example

ds = rasgo.get.dataset(fqtn="BATTING_AVERAGES")

ds2 = ds.ratio_with_shrinkage(numerator = 'HITS', 
              denom = 'AT_BATS', 
              min_cutoff = 500)

Source Code

https://github.com/rasgointelligence/RasgoTransforms/blob/main/rasgotransforms/rasgotransforms/transforms/ratio_with_shrinkage/snowflake/ratio_with_shrinkage.sql