An R Package for Evaluating Expertise Indices for Research Strength Assessment R package xxdi version 1.26.4 Institutional performance assessment remains a key challenge to a multitude of stakeholders. Existing indicators such as h-type indicators, g-type indicators, and many others do not reflect expertise of institutions that defines their research portfolio. The package offers functionality to compute and visualise two novel indices: the x-index and the xd-index. The x-index evaluates an institution's scholarly expertise within a specific discipline or field, while the xd-index provides a broader assessment of overall scholarly expertise considering an institution's publication pattern and strengths across coarse thematic areas. These indices offer a nuanced understanding of institutional research capabilities, aiding stakeholders in research management and resource allocation decisions. Lathabai, H.H., Nandy, A., and Singh, V.K. (2021) <doi:10.1007/s11192-021-04188-3>. Nandy, A., Lathabai, H.H., and Singh, V.K. (2023) <doi:10.5281/zenodo.8305585>. This package provides the h-, g-, x-, xd-indices, and their variants for use with standard format of Web of Science (WoS) scrapped datasets. Software Depends: R (>= 4.4.2.0) Imports: agop (>= 0.2.4), dplyr (>= 1.1.4), ggplot2 (>= 3.5.0), stats (>= 4.3.3), tidyr (>= 1.3.1) Nilabhra R Das <nr.das@yahoo.com> Comprehensive R Archive Network (CRAN) Nilabhra R Das [cre, aut] (ORCID: <https://orcid.org/0000-0001-8187-0080>), Abhirup Nandy [aut] (ORCID: <https://orcid.org/0000-0001-8618-0847>) GPL-3 2026-04-30 application/tgz https://CRAN.R-project.org/package=xxdi doi:10.32614/CRAN.package.xxdi