There are several ways to measure the reach and impact of a scholar's work. Some involve measuring the work of the particular author and others look at the relative rankings of the journals the author publishes in compared to other journals in that field. Some of these measures are:
Impact Factor:The impact factor is a measurement of journal reach and impact. It is used to rank journals by their importance relative to other journals in the field.
Citation Analysis: Simply counting the number of times other authors have referred to a particular article in their own work.
H-Index: The h-index is a measure of the reach and impact of a particular individual author.
Altmetrics: Altmetrics are designed to be complementary to traditional publication metrics; instead of measuring citations in journals, they look at mentions of articles and authors on less traditional publication platforms such as social media platforms, media, reference managers and Faculty of 1000.
Alexander I. Pudovkin. (2018). Comments on the Use of the Journal Impact Factor for Assessing the Research Contributions of Individual Authors. Frontiers in Research Metrics and Analytics , Vol 3 (2018). https://doi.org/10.3389/frma.2018.00002/full.
Barnes, C. (2017). The h-index Debate: An Introduction for Librarians. Journal of Academic Librarianship, 43(6), 487–494. https://doi.org/10.1016/j.acalib.2017.08.013.
Bornmann, L., & Haunschild, R. (2018). Do altmetrics correlate with the quality of papers? A large-scale empirical study based on F1000Prime data. PLoS ONE, 13(5), 1–12. https://doi.org/10.1371/journal.pone.0197133.
Brock, J. (2019). The allure of the journal impact factor holds firm, despite its flaws. Nature Index. https://www.natureindex.com/news-blog/allure-journal-impact-factor-holds-firm-despite-flaws.
Bryan D. Neff, & Julian D. Olden. (2010). Not So Fast: Inflation in Impact Factors Contributes to Apparent Improvements in Journal Quality. BioScience, (6), 455. https://doi.org/10.1525/bio.2010.60.6.9.
Chawla, D.S. (2018). What's wrong with the journal impact factor in 5 graphs. Nature Index. https://www.natureindex.com/news-blog/whats-wrong-with-the-jif-in-five-graphs
Dadkhah, M., Borchardt, G., Lagzian, M., & Bianciardi, G. (2017). Academic Journals Plagued by Bogus Impact Factors. Publishing Research Quarterly, 33(2), 183–187. https://doi.org/10.1007/s12109-017-9509-4.
Fernandez-Llimos, F. (2018). Differences and similarities between Journal Impact Factor and CiteScore. Pharmacy Practice, 16(2), 1–3. https://doi.org/10.18549/PharmPract.2018.02.1282.
Frieder M. Paulus, Nicole Cruz, & Sören Krach. (2018). The Impact Factor Fallacy. Frontiers in Psychology, Vol 9 (2018). https://doi.org/10.3389/fpsyg.2018.01487/full.
Pandita, R., & Singh, S. (2015). Impact of Self-Citations on Impact Factor: A Study Across Disciplines, Countries and Continents. Journal of Information Science Theory and Practice, Vol 3, Iss 2, Pp 42-57 (2015), (2), 42. https://doi.org/10.1633/JISTaP.2015.3.2.4.
Loomba, R. S., & Anderson, R. H. (2018). Are we allowing impact factor to have too much impact: The need to reassess the process of academic advancement in pediatric cardiology? Congenital Heart Disease, 13(2), 163–166. https://doi.org/10.1111/chd.12593.
Marc AndrÃ© Meyers, & Haocheng Quan. (2017). The use of the h-index to evaluate and rank academic departments. Journal of Materials Research and Technology, Vol 6, Iss 4, Pp 304-311. https://doi.org/10.1016/j.jmrt.2017.09.004.
William Cabos, & Juan Miguel Campanario. (2018). Exploring the Hjif-Index, an Analogue to the H-Like Index for Journal Impact Factors. Publications, Vol 6, Iss 2, p 14.. https://doi.org/10.3390/publications6020014.
Wouters, P. (2019). Rethinking Impact Factors: Better Ways to Judge a Journal. Nature, Vol 569, Pp 621-623. https://www.nature.com/articles/d41586-019-01643-3
Yuret, T. (2016). Is it easier to publish in journals that have low impact factors? Applied Economics Letters, 23(11), 801–803. https://doi.org/10.1080/13504851.2015.1109034.