Measures overall list and specific measures I use.
Citation counts: They represent the number of times an article has been referenced by another academic source. There are many sources for citation counts including Google Scholar. The NIH iCite ( https://icite.od.nih.gov/analysis ) is a well respected source for citation analysis for PubMed articles. An example; https://icite.od.nih.gov/analysis?pmids=21840587 [ Usage restrictions depend on specific measure ]
Citation counts iCite: Official source The NIH iCite is a well respected source for citation analysis for PubMed articles, it only counts citations from other PubMed articles. [ Free to access and reference ]
Relative Citation Ratio (RCR): Official source It represents a Citation-based measure of scientific influence of one or more articles, from iCite. [ Free to access and reference ]
Citation based influence scores: Going deeper than just number of citation references, these scores weigh other factors and try to place a more calculated and meaningful value on citation references. There are several trusted measures including S Impact Factor (IF). The NIH iCite ( https://icite.od.nih.gov/analysis ) system uses Relative Citation Ratio (RCR) for assigning a more comprehensive value on associated PubMed citations. An example; https://icite.od.nih.gov/analysis?pmids=21840587 [ Usage restrictions depend on specific measure ]
Google Scholar Citation counts: Official source Google scholar is Google's academic search site. It lists citation counts across all academic disciplines . Because its scope is broad and includes less professional sources and may sometime include duplicates, its citation counts can sometimes be inflated. An example of a Scholar search; https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=kidney+failure&btnG= [ Free to access and reference ]
Hirsch index (also know as h-index): Key Reference It varies by sources such as Scopus (Elsevier) or Web of Science (Clarivate). It is a single-number metric intended to quantify both the productivity and citation impact of a person or journal. Its based on the number of articles and the number of reference those articles receive. A higher h-index represent consistently impactful work (more publications with high citation counts). It balances productivity (number of papers) with how often those papers are cited (citation count), making it less skewed by one or two extremely highly cited papers. [ Usage restrictions depend on specific measure ]
Goggle Scholar Metrics: Official source Google Scholar itself does not provide an “impact factor” or “score” the way some other databases do (for instance, Clarivate’s Web of Science has the Journal Impact Factor, and Scopus has the CiteScore). However, Google Scholar publishes Google Scholar Metrics, which ranks journals by two metrics over a recent five-year period ( h5-index , and h5-median ). [ Free to access and reference ]
Google Scholar h5-index: Official source Limited to top 100 journals within a focus area. The h5-index is similar to the well-known h-index, but it specifically focuses on articles published within the last five full calendar years. For example, if a journal has an h5-index of 20, it means that there are at least 20 articles published by that journal in the last five years that each have at least 20 citations. [ Free to access and reference ]
Google Scholar h5-median: Official source Limited to top 100 journals within a focus area. Once the h5-index is found, the set of publications used to compute the h5-index is identified. The h5-median is the median (middle) number of citations for those articles in that set. If the h5-index of a journal is 20, so at least 20 articles with at least 20 citations each. The h5-median is the median citation count among them. [ Free to access and reference ]
Impact Factor (IF) by Clarivate: Official source Published in its Journal Citation Reports (JCR). 2-year Impact Factor: for example, 2025, is calculated by dividing the total number of citations in 2025 to items published in that journal during the previous two years (2023 and 2024) by the total number of “citable items” that the journal published in 2023 and 2024 [ Proprietary; subscription or permission required for usage ]
CiteScore by Scopus (Elsevier): Official source CiteScore reflects the average number of citations in a particular year to papers published in the previous four years. For example, the 2025 CiteScore is based on citations in 2025 to articles published in 2021–2024, divided by the total number of “citable items” from 2021–2024.CiteScore is Elsevier’s proprietary metric. [ Single usage is free; extensive usage may require permission ]
SCImago Journal Rank (SJR) : Official source By the SCImago research group in Spain and it uses citation data from the Scopus database. SCImago then applies its own network-based algorithm (similar to the PageRank algorithm) to produce the SJR value for each journal. [ Free to access and reference ]
Altmetric Score: Official source Captures the online visibility and engagement surrounding a article (or book etc.). Its a complement to traditional metrics, designed to measure the online buzz and real-world reach of scholarly outputs (X Twitter, Facebook, News etc.) [ Single usage is free; extensive usage may require permission ]
Chinese Science Citation Database (CSCD): Official source This remains the dominant metric for STEM fields (science, technology, engineering, medicine) and is used extensively throughout China's scientific research community. Primarily focus on Chinese journals published in Chinese or English, but they do include international citations and references as well. [ Proprietary; subscription or permission required for usage ]
Chinese Social Sciences Citation Index (CSSCI): Official source By Nanjing University in China, CSSCI is a citation index covering core Chinese academic journals primarily in the humanities and social sciences. Primarily focus on Chinese journals published in Chinese or English, but they do include international citations and references as well. [ Proprietary; subscription or permission required for usage ]
Medline: Official source PubMed classification by the NIH, refers to both journal status and article status. Journals are reviewed and high quality journals are given medline status. Articles within those journals are individually judged and can be given medline status. Articles from a medline journal may have both medline articles and non medline articles. [ Free to access and reference ]
PubMed Citation Bar measures
* This indicates its a high value article, the bar should also be blue. Its an score based on many items in the Citation Bar.
n This is for new articles, anything under 2 years old, based on date entered in the PubMed system [crdt]
t This is for Trending, articles that are new (generally with 30 days), that are getting a lot of views.
m This is for medline articles.
Cited - The number of times cited from iCite.
RCR - Relative Citation Ratio (RCR) from iCite.
ALT - Altmetric Score for the specific article.
Sch - Google scholar for the specific article.
Top-J - One of the 7 top Journals listed on the PubMed Citation Bar extension popup.
SJR - SCImago Journal Rank (SJR) for the journal for the article.
# Articles - Total number of 2023 PubMed article for the journal.
Rank - Journal rank based on total number of PubMed articles for that journal in 2023.
Medine - Medline status of the article (by PubMed).