NEWS

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footBayes 2.1.0 (2026-10-07)

New models

• Add the Dixon-Coles model ("dixon_coles") to stan_foot(), static and dynamic, and to mle_foot().
• Add the negative binomial model ("neg_bin") to mle_foot().

Dynamic models in stan_foot()

• Add dynamic_par to choose the evolution variance: a common variance (common_sd, Owen, 2011) or a variance inflation after the summer break (kl_variance and periods_per_season, Koopman and Lit, 2015).
• Add dynamic_weight for the weighted dynamic models with commensurate priors (Macrì Demartino, Egidi and Torelli, 2026), with spike and slab hyperpriors set through dynamic_par$spike and dynamic_par$slab.

Other changes

• print.stanFoot() with teams keeps all the global parameters and shows the team names in the team-indexed parameters.
• foot_prob() supports the "dixon_coles" and "neg_bin" MLE models.
• Add an identifiability constraint to the Bradley-Terry-Davidson Stan models.
• Extend the confidence intervals of mle_foot() to the model-specific parameters and move the MLE simulations to the internal simulate_goals_mle().
• Rewrite the vignette.

Bug fixes

• Fix the likelihood of the static bivariate Poisson model.
• Draw y_rep and y_prev of the bivariate Poisson models from the bivariate Poisson distribution.
• Rewrite the diagonal-inflated bivariate Poisson model as in Karlis and Ntzoufras (2003), with the new parameter draw_dist for the draws.
• Return diff_y_prev in the bivariate Poisson and diagonal-inflated bivariate Poisson models.
• Fix the AIC and BIC of mle_foot() to count only the free parameters of each model.
• Fix foot_prob() for MLE models, which used object$home instead of object$home_effect.
• Fix compare_foot() with NA rows in a probability matrix, which misaligned the outcomes of the following elements of source.
• Match ranking in stan_foot() to the teams by name instead of by position, with informative errors for missing or duplicated teams.
• Fix the observed frequencies in pp_foot(type = "aggregated") for models fitted with predict > 0.

Documentation

• Update foot_abilities() for the six MLE models.
• Fix the documentation of italy, priors, btd_foot(), compare_foot(), plot_logStrength() and of norm_method and rho in stan_foot().

footBayes 2.0.1

• Updated vignette.
• Correct typo in foot_compare() description.
• Correct typo in pp_foot() description.

footBayes 2.0.0 (2025-05-16)

• Migration from rstan interface to CmdStanR interface.
• Add support for the VI, pathfinder and laplace algorithms.
• Add pre-compiled CmdStan models using the package instantiate.
• Add AIC and BIC output elements in mle_foot().
• Add Bayesian static/dynamic Negative Binomial model in stan_foot().
• Minor ggplot2 edits on foot_rank(), foot_abilities() and pp_foot().
• Updated vignette.

footBayes 1.0.0 (2025-01-09)

• Bradley-Terry model for abilities.
• Dynamic ranking in the models.
• Updated vignette.
• Probabilistic predictive performance (pseudo-R squared, Brier score, etc.).

footBayes 0.2.0 (2023-08-31)

• Inclusion of diagonal-inflated bivariate Poisson and zero-inflated Skellam models.
• Minor edits and drop engsoccerdata dependence.
• Updated vignette.

footBayes 0.1.0 (2022-02-21)

• First submission to CRAN.