I’m interesting in learning about how to rate and rank individuals in a group who only interact/compete in a pairwise fashion (i.e., systems like the ELO rating system for chess).

- Are there are any go-to methods or more accurate and advanced methods out there?
- Are there any R packages that make implementation easy?
- Are there methods that can use auxiliary information as well as the outcome of a match/game?
- Are there methods that can better use the information of winning margin as opposed to dichotomous win/lose?
- What should I be looking for in the literature?

**Answer**

Regarding “how to do it in R”, the prefmod package http://cran.r-project.org/web/packages/prefmod/index.html is meant for preference analysis with paired comparisons, rankings and ratings. It fits Bradley-Terry models and pattern models with object and subject covariates. See my answer here How to fit Bradley–Terry–Luce model in R, without complicated formula? for a short intro, or this paper http://www.jstatsoft.org/v48/i10 for more info.

**Attribution***Source : Link , Question Author : dcl , Answer Author : Community*