underdisp: Diagnostics and Models for Underdispersed Count Data

Tools for detecting and modeling underdispersion in count data (conditional variance below the conditional mean), a phenomenon overlooked by the Poisson and negative binomial defaults. Provides a screening diagnostic that benchmarks at-risk dispersion against a zero-truncated Poisson; the continuous parameter binomial (CPB) regression and its zero-truncated variant, with an interpretable observation-specific bound and high-dimensional fixed-effects support; validated bootstrap (for coefficients) and profile-likelihood (for the dispersion parameter) inference; and quantities of interest including predicted probabilities and the implied ceiling. The likelihood is implemented in C++ for speed.

Version:	0.1.0
Depends:	R (≥ 4.0)
Imports:	Rcpp, stats, MASS, VGAM, graphics, methods, numDeriv
LinkingTo:	Rcpp
Suggests:	sandwich, pscl, DHARMa, testthat (≥ 3.0.0), knitr, rmarkdown, broom, modelsummary, texreg
Published:	2026-08-20
DOI:	10.32614/CRAN.package.underdisp
Author:	Benjamin E. Bagozzi [aut, cre]
Maintainer:	Benjamin E. Bagozzi <bagozzib at udel.edu>
BugReports:	https://github.com/bagozzib/underdisp/issues
License:	GPL-3
URL:	https://github.com/bagozzib/underdisp
NeedsCompilation:	yes
Materials:	README, NEWS
CRAN checks:	underdisp results

Documentation:

Reference manual:	underdisp.html , underdisp.pdf
Vignettes:	Detecting and Modeling Underdispersed Counts (source, R code)

Downloads:

Package source:	underdisp_0.1.0.tar.gz
Windows binaries:	r-devel: underdisp_0.1.0.zip, r-release: underdisp_0.1.0.zip, r-oldrel: underdisp_0.1.0.zip
macOS binaries:	r-release (arm64): underdisp_0.1.0.tgz, r-oldrel (arm64): underdisp_0.1.0.tgz, r-release (x86_64): underdisp_0.1.0.tgz, r-oldrel (x86_64): underdisp_0.1.0.tgz

Linking:

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