Scale Mixture of Skew-Normal Linear Mixed Models

It fits scale mixture of skew-normal linear mixed models using either an expectation–maximization (EM) type algorithm or its accelerated version (Damped Anderson Acceleration with Epsilon Monotonicity, DAAREM), including some possibilities for modeling the within-subject dependence .

Post-Estimation Functions for Generalized Linear Mixed Models

Several functions for working with mixed effects regression models for limited dependent variables. The functions facilitate post-estimation of model predictions or margins, and comparisons between model predictions for assessing or probing moderation. Additional helper functions facilitate model comparisons and implements simulation-based inference for model predictions of alternative-specific outcome models. See also, Melamed and Doan (2024, ISBN: 978-1032509518).

Fast Fitting of Stable Isotope Mixing Models with Covariates

Fast fitting of Stable Isotope Mixing Models in R. Allows for the inclusion of covariates. Also has built-in summary functions and plot functions which allow for the creation of isospace plots. Variational Bayes is used to fit these models, methods as described in: Tran et al., (2021) .

Maximum Likelihood Estimation for Generalized Linear Mixed Models

Maximum likelihood estimation for generalized linear mixed models via Monte Carlo EM. For a description of the algorithm see Brian S. Caffo, Wolfgang Jank and Galin L. Jones (2005) .

Mixed Model Association Test for GEne-Environment Interaction

Use a 'glmmkin' class object (GMMAT package) from the null model to perform generalized linear mixed model-based single-variant and variant set main effect tests, gene-environment interaction tests, and joint tests for association, as proposed in Wang et al. (2020) .

Reproducible Ecological Generalized Linear Mixed Model Pipelines

Fits and compares generalized linear mixed models for multiple ecological responses and environmental predictors. The package supports additive and temporal-interaction candidate models, AICc model selection, likelihood-ratio tests, coefficient extraction, Nakagawa R-squared, simulation-based diagnostics, figures, and spreadsheet exports. Model selection follows Burnham and Anderson (2002, ISBN:9780387953649); marginal and conditional R-squared follow Nakagawa and Schielzeth (2013) .

Estimate (Generalized) Linear Mixed Models with Factor Structures

Utilizes the 'lme4' and 'optimx' packages (previously the optim() function from 'stats') to estimate (generalized) linear mixed models (GLMM) with factor structures using a profile likelihood approach, as outlined in Jeon and Rabe-Hesketh (2012) and Rockwood and Jeon (2019) . Factor analysis and item response models can be extended to allow for an arbitrary number of nested and crossed random effects, making it useful for multilevel and cross-classified models.

Penalized ECME Estimation for Censored Linear Mixed Models

Fits Gaussian linear mixed models with a random intercept when the response is subject to left, right, and/or interval censoring, using the Expectation/Conditional Maximization Either (ECME) algorithm of Liu and Rubin (1994) in the spirit of the fast censored-response mixed-model algorithm of Vaida and Liu (2009). Simultaneous estimation and variable selection is supported through coordinate-descent penalized maximization with Lasso, Adaptive Lasso, SCAD, MCP, Elastic Net, and Ridge penalties (no penalty is also supported). The random intercept is integrated out by Gauss-Hermite quadrature at every iteration, and the two ECME conditional-maximization steps respectively maximize the expected penalized complete-data objective (for the regression coefficients) and the actual observed-data marginal likelihood (for the variance components), which is the defining feature of ECME relative to plain ECM/EM. The package provides a single-fit engine, a sequential/parallel penalty-parameter grid search with information-criterion or cross-validated selection, data-dependent or user-supplied lambda grids, and an Expectation-Maximization based treatment of a completely missing (at random) response, sharing the same truncated-normal machinery used for censoring. References: Liu and Rubin (1994) "The ECME algorithm: A simple extension of EM and ECM with faster monotone convergence" ; Vaida and Liu (2009) "Fast Implementation for Normal Mixed Effects Models With Censored Response" .

Robust Bayesian Longitudinal Regularized Semiparametric Mixed Models

Our recently developed fully robust Bayesian semiparametric mixed-effect model for high-dimensional longitudinal studies with heterogeneous observations can be implemented through this package. This model can distinguish between time-varying interactions and constant-effect-only cases to avoid model misspecifications. Facilitated by spike-and-slab priors, this model leads to superior performance in estimation, identification and statistical inference. In particular, robust Bayesian inferences in terms of valid Bayesian credible intervals on both parametric and nonparametric effects can be validated on finite samples. The Markov chain Monte Carlo algorithms of the proposed and alternative models are efficiently implemented in 'C++'.

Generalized Fiducial Inference for Normal Linear Mixed Models

Simulation of the generalized fiducial distribution for normal linear mixed models with interval data. Fiducial inference is somehow similar to Bayesian inference, in the sense that it is based on a distribution that represents the uncertainty about the parameters, like the posterior distribution in Bayesian statistics. It does not require a prior distribution, and it yields results close to frequentist results. Reference: Cisewski and Hannig (2012) .