Pairwise Comparison Tools for Large Language Model-Based Writing Evaluation R package pairwiseLLM version 1.1.0 Provides a unified framework for generating, submitting, and analyzing pairwise comparisons of writing quality using large language models (LLMs). The package supports live and/or batch evaluation workflows across multiple providers ('OpenAI', 'Anthropic', 'Google Gemini', 'Together AI', and locally-hosted 'Ollama' models), includes bias-tested prompt templates and a flexible template registry, and offers tools for constructing forward and reversed comparison sets to analyze consistency and positional bias. Results can be modeled using Bradley–Terry (1952) <doi:10.2307/2334029> or Elo rating methods to derive writing quality scores. For information on the method of pairwise comparisons, see Thurstone (1927) <doi:10.1037/h0070288> and Heldsinger & Humphry (2010) <doi:10.1007/BF03216919>. For information on Elo ratings, see Clark et al. (2018) <doi:10.1371/journal.pone.0190393>. Software Depends: R (>= 4.1) Imports: curl, dplyr, httr2, jsonlite, rlang, stats, tibble, tidyselect, tools, utils Suggests: BradleyTerry2, EloChoice, knitr, mockery, purrr, readr, rmarkdown, sirt, stringr, testthat (>= 3.0.0), tidyr, withr Sterett H. Mercer <sterett.mercer@ubc.ca> Comprehensive R Archive Network (CRAN) Sterett H. Mercer [aut, cre] (ORCID: <https://orcid.org/0000-0002-7940-4221>) MIT + file LICENSE (https://CRAN.R-project.org/package=pairwiseLLM/LICENSE) 2025-12-22 application/tgz https://CRAN.R-project.org/package=pairwiseLLM doi:10.32614/CRAN.package.pairwiseLLM