Ternary Plots for Trinomial Regression Models - Version 3.2.0 - Package overview

Oct 26, 2026

plot3logit provides ternary plots for interpreting regression coefficients in trinomial regression models. The package graphically represents covariate effects by mapping changes in regressor values to the dependent variable’s probability distribution, including single and composite covariate changes. It reads estimates from categorical and ordinal trinomial logit regressions (e.g., ordinal, mlogit, nnet, MASS, VGAM outputs) and builds field3logit objects visualized via autoplot() and plot(), including confidence regions since version 2.0.0.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages26

Reading Time1 h 6 min

AccessFree to download

plot3logit-package

add_confregions

autoplot.Hfield3logit

extract3logit

field3logit

gg3logit

labels

multifield3logit

stat_3logit

stat_conf3logit

stat_field3logit

TernaryField

USvote2016

Index

Package ‘plot3logit’ May 9, 2026 Type Package Title Ternary Plots for Trinomial Regression Models Version 3.2.0 Author Flavio Santi [cre, aut](ORCID: <[https://orcid.org/0000-0002-2014-1981](https://orcid.org/0000-0002-2014-1981)>), Maria Michela Dickson [aut](ORCID: <[https://orcid.org/0000-0002-4307-0469](https://orcid.org/0000-0002-4307-0469)>), Giuseppe Espa [aut](ORCID: <[https://orcid.org/0000-0002-0331-3630](https://orcid.org/0000-0002-0331-3630)>), Diego Giuliani [aut](ORCID: <[https://orcid.org/0000-0002-7198-6714](https://orcid.org/0000-0002-7198-6714)>) Maintainer Flavio Santi URL [https://www.flaviosanti.it/software/plot3logit/](https://www.flaviosanti.it/software/plot3logit/) BugReports [https://github.com/f-santi/plot3logit/issues/](https://github.com/f-santi/plot3logit/issues/) Description An implementation of the ternary plot for interpreting regression coefficients of trinomial regression models, as proposed in Santi, Dickson and Espa (2019) . Ternary plots can be drawn using either 'ggtern' package (based on 'ggplot2') or 'Ternary'package (based on standard graphics) . The package and its features are illustrated in Santi, Dickson, Espa and Giuliani (2022) . Depends R (>= 4.5), ggtern (>= 4.0.0), Ternary (>= 2.3.5) Imports dplyr, ellipse, forcats, generics, ggplot2 (>= 4.0.1), graphics, grDevices, lifecycle, magrittr (>= 2.0.3), purrr, Rdpack, stats, stringr, tibble, tidyr, tidyselect, utils Suggests knitr, MASS (>= 7.3.65), mlogit, nnet, ordinal, rmarkdown, VGAM, testthat License GPL (>= 2) LazyData true NeedsCompilation no Encoding UTF-8 RoxygenNote 7.3.2 2 plot3logit-package Repository CRAN VignetteBuilder knitr RdMacros Rdpack, lifecycle Date/Publication 2025-12-19 20:20:09 UTC Contents plot3logit-package ..................................... 2 add_confregions ....................................... 4 autoplot.Hfield3logit .................................... 6 cross_ 1year ......................................... 7 extract3logit ......................................... 8 field3logit .......................................... 10 gg3logit ........................................... 14 labels ............................................ 15 multifield3logit ....................................... 16 stat_ 3logit .......................................... 18 stat_conf3logit ....................................... 19 stat_field3logit ....................................... 21 TernaryField ......................................... 23 USvote2016 ......................................... 24 Index 25 | plot3logit-package | Ternary Plots for Trinomial Regression Models | | --- | --- | Description An implementation of the ternary plot for interpreting regression coefficients of trinomial regression models, as proposed in Santi et al. (2019) . For details on the features of the package, see Santi et al. (2022) . Details The package permits the covariate effects of trinomial regression models to be represented graphically by means of a ternary plot. The aim of the plots is helping the interpretation of regression coefficients in terms of the effects that a change in regressors’ values has on the probability distribution of the dependent variable. Such changes may involve either a single regressor, or a group of them (composite changes), and the package permits both cases to be represented in a user-friendly way. Methodological details are illustrated and discussed in Santi et al. (2019) . The package can read the results of both categorical and ordinal trinomial logit regression fitted by various functions (see extract3logit()) and creates a field3logit object which may be represented by means of functions autoplot() and plot() . The plot3logit package inherits graphical classes and methods from the package ggtern (Hamilton and Ferry 2018) wh

FAQs

What does plot3logit do for trinomial regression models?

It implements ternary plots that help interpret regression coefficients by visualizing how covariate changes affect the probability distribution of the dependent variable.

Which kinds of regression outputs can field3logit() read?

It can read estimates from ordinal package functions (clm/clm2), mlogit (mlogit), nnet (multinom), MASS (polr), and VGAM (vgam/vglm), and it can also take explicit estimates.

How are the ternary plots produced and extended in later versions?

field3logit objects can be visualized using functions like autoplot() and plot(). Since version 2.0.0, the package can compute and draw confidence regions for covariate effects.

Oct 26, 2026

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