welo: An R package for weighted and standard Elo rates

Abstract

This paper describes the characteristics of the welo package, dedicated to calculating the weighted and unweighted (or standard)
Elo rates in tennis. The Elo rates are one of the most accurate proxies of the strength of players/teams. In the standard version, the
Elo rates are dynamically obtained using the outcome of the two players. In the recent paper of Angelini et al. (2022), the weighted
version of the Elo rates (labeled as WElo) has been proposed in order to take into account not only the outcome of the matches but also the
scoreline. The present work illustrates the main features of the R package, which allows the user to easily and quickly obtain the WElo
and Elo rates, as well as the predicted probabilities of winning.