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Calculate eta-shrinkage

Source: R/calculate_shrinkage.R
calculate_shrinkage.Rd

Calculate eta-shrinkage, measure of how much information is available to update individual estimates away from the population value.

Usage

calculate_shrinkage(.res)

Arguments

.res

output object (mipdeval_results) from run_eval(), or data.frame with raw results.

Value

tibble

Details

Shrinkage for population PK models was first defined in this paper by Savic and Karlsson: https://pmc.ncbi.nlm.nih.gov/articles/PMC2758126/. It is a measure of how much information is available to update individual estimates away from the population value. In principle, if there is no information at all (i.e. in the case of population estimates only), shrinkage will be 100%. In the case of fully informed Bayesian estimates (unlikely to be achieved in practice), shrinkage is 0%. In most practical scenarios with limited sampling, shrinkage will be between 10-40%. When shrinkage is higher than 50% or so, one could argue there is limited benefit of sampling at all. So the shrinkage reported in this package can be used to evaluate whether the sampling was efficient, and how shrinkage could be reduced with additional sampling.