Software
R packages developed and maintained by SADL for applied statistical modeling in political methodology.
Open Source
Tools for detecting, modeling, and estimating count and ordered-outcome data structures that standard defaults overlook.
Diagnostics and models for underdispersed count data — conditional variance below the conditional mean, which Poisson and negative binomial defaults overlook. Includes a screening diagnostic, continuous-parameter binomial regression with zero-truncated variants, bootstrap and profile-likelihood inference, and predicted probabilities. The likelihood is implemented in C++.
864 downloads from CRAN
install.packages("underdisp")
Inflated ordered probit and logit models: the zero-inflated ordered probit of Harris and Zhao (2007) plus middle- and top-inflated extensions. Provides oprobit()/ologit() and iop()/iol(), panel versions with random intercepts and fixed effects, correlated-error variants (ZiOPC/MiOPC/TiOPC), and category-specific split equations.
608 downloads from CRAN
install.packages("iop")
Implements: Modeling Two Types of Peace: The Zero-Inflated Ordered Probit (ZiOP) Model in Conflict Research
Full source, issues, and release notes are hosted on GitHub at github.com/bagozzib.