Dear Colleagues,
PriorGen is an R package that generates priors in the form of beta and Gamma distributions got proportions. You may find it useful for the generation of priors on the sensitivity/specificity of diagnostic tests and the prevalence of disease.
The findbeta function estimates the parameters of a Beta distribution based on the existing prior beliefs about the mean (or the median or the mode) and whether it is lower or greater that a certain value with a pre-specified certainty (usually set at 95%).
The findbetaqq function estimates the parameters of a Beta distribution based on the existing prior beliefs about the values of two distinct percentiles.
The findbetamupsi function estimates:
1. the parameters of a Beta distribution for the expected mean of a proportion -usually the prevalence of disease/infection.
2. the parameters of a Gamma distribution expressing our prior belief about the variability (ψ) of the prevalence estimates across the units of the area/region under consideration.
You may download it from here: https://cran.r-project.org/package=PriorGen
Hope you find it helpful and, of course, any comments/suggestions are most welcome.
Polychronis
To cite package ‘PriorGen’ in publications use:
Polychronis Kostoulas (2018). PriorGen: Generates Prior Distributions
for Proportions. R package version 1.1.2.
https://CRAN.R-project.org/package=PriorGen
A BibTeX entry for LaTeX users is
@Manual{,
title = {PriorGen: Generates Prior Distributions for Proportions},
author = {Polychronis Kostoulas},
year = {2018},
note = {R package version 1.1.2},
url = {https://CRAN.R-project.org/package=PriorGen},
}