Measuring Research Impact

Authors choose journals to submit their manuscript by evaluating the reputation of the journal, with several metrics as mentioned below.

1. Impact Factor The impact factor (IF) is a measure of the frequency with which the average article in a journal has been cited for a particular year. It is also used to measure the ranking of a journal by calculating the times its articles are cited.
2. 5 Year IF The 5-year journal Impact Factor is the average number of times articles from the journal published in the past five years have been cited.
3. Eigen Factor Eigen factor scores give a measure of how likely a journal is to be used and reflect how frequently an average researcher would access content from that journal.
4. SNIP Source Normalized Impact per Paper (SNIP) measures contextual citation impact by weighting citations based on the total number of citations in a subject field.
5. SJR The SCImago Journal & Country Rank portal includes journals and country scientific indicators developed from information in the Scopus database.
6. Immediacy Index The Immediacy Index is the average number of times an article is cited in its published year.

The following journal impact metrics are used to measure impact factors in Web of Science.

1. Impact Factor Developed in the 1960s, defined as the average number of times articles from the journal published over a defined time were cited. Available in the Journal Citation Report (JCR).
   Calculation of 2020 IF:
   A = citations to 2018–2019 articles during 2020
   B = total citable items published in 2018–2019
   A ÷ B = 2020 Impact Factor
2. 5 Year IF Represents the average number of citations articles received in the past five years according to the JCR year.
   Calculation: Total citations (500) ÷ Total articles in 5 years (100) = 5-Year IF of 5
3. Immediacy Index Average number of times an article is cited in its published year, indicating how quickly articles in a journal are picked up.
   Calculation: Cites in 2022 to 2022 articles (6000) ÷ Articles published in 2022 (400) = JII of 15
4. Eigen Factor Similar to Google's PageRank, leverages the entire citation network to evaluate journal significance. Accessible at eigenfactor.org.
   Example: Search "Nature" on eigenfactor.org or in JCR to view and interpret its Eigenfactor value within the scientific community.
5. Essential Science Indicators ESI ranks top-performing research across 22 fields based on publication and citation data from 11,000+ journals. Updated bimonthly via SCIE and SSCI.
   Example: Author A: 10 articles, 100 citations. Author B: 5 articles, 150 citations. Despite fewer publications, Author B's higher average citations may earn a higher ESI ranking.

The following journal impact metrics are used to measure impact factors in Scopus.

1. SJR SCImago Journal Rank assesses scientific prestige by measuring weighted citations, giving more weight to citations from prestigious journals.
   Calculation: Weighted citations (800) ÷ Total documents (100) = SJR of 8
2. SNIP Source Normalized Impact per Paper measures citation impact normalized against the citation potential of the subject field.
   Calculation: Journal Z avg citations (10) ÷ Field avg citations (5) = SNIP of 2
3. CiteScore Measures average citations received per document over a specific period.
   Calculation: Total citations (500) ÷ Total documents (100) = CiteScore of 5

The following journal impact metric is used to measure impact factors in Google Scholar.

1. Scholar Metrics A freely accessible tool providing rankings of journals and articles based on citation metrics — helping researchers decide where to publish and which research to follow.
   Example: Journal X: h5-index = 20, h5-median = 50. At least 20 articles in the past 5 years each received ≥ 20 citations, with a median of 50.

Article Level Metrics (ALMs) measure the overall performance and reach of a single article, offering a more comprehensive view of impact compared to traditional citation counts alone.

1. Citations The number of times the article has been cited by other articles — the most traditional metric of impact.
2. Views The number of times the article has been viewed or downloaded, indicating level of interest.
3. Social Mentions Times the article has been shared or mentioned on social media, demonstrating public reach and engagement.
4. Bookmarks Times the article has been bookmarked or saved, indicating perceived value to readers.
5. Comments Comments and discussions generated by the article, showing engagement with its content.

The following resources provide article-level metrics across a wide spectrum of scholarly output.

1. Altmetric Tracks online activity including mainstream media, social media, and publisher downloads for scholarly literature mentions, producing an Altmetric score.
2. PLOS ALMs PLOS provides article-level metrics such as views and downloads for articles published in its journals.
3. Bookmetrix Analytics platform for books, providing insights into reach and impact for authors, publishers, and institutions.
4. Dimensions Discovery and analytics platform with metrics including citations, Relative Citation Ratio, and altmetrics for 90M+ publications.
5. CINAHL Indexes nursing, consumer health, and allied health journals with article-level metrics from Plum Analytics.
6. Scopus PlumX Provides PlumX Metrics assessing research impact through citations, social media mentions, and media coverage.
7. Web of Science Provides citation counts per article across its indexed scholarly literature.
8. Google Scholar Searches scholarly literature on the web and provides citation counts per article.
9. PubMed Database of 30M+ citations for biomedical literature from MEDLINE, life science journals, and online books.
10. Mendeley Provides readership information, included in Scopus PlumX Metrics.

Various tools capture and present altmetrics — amalgamating data from traditional and modern sources for a richer picture of research impact.

1. Altmetric Backed by Digital Science; adopted by Springer, Nature Publishing Group, Scopus, and BioMed Central. Scores articles based on mentions, source quality, and frequency. For-profit entity.
2. ImpactStory Open-source altmetric tool drawing from Facebook, Twitter, PubMed, Scopus, Mendeley, Wikipedia, and more. Reports raw scores and percentiles. Free embeddable widget. Nonprofit entity.
3. Plum Analytics Tracks metrics for articles, book chapters, datasets, presentations, and source code. Provides custom departmental productivity reports for universities and research institutions.
4. PLOS Open-source application storing and reporting configurable performance data on research articles, customizable to include additional ALM data sources.

Author impact is typically assessed by the number of citations their work garners. Establishing an author profile with a persistent identifier like ORCID ID or Researcher ID helps track a complete citation record.

Author metrics gauge the frequency of citations to an author's work, illustrating the reach and impact of their contributions. These metrics are crucial for grant applications, tenure evaluations, promotion decisions, and performance reviews.

A widely-used metric that quantifies both the productivity and impact of a researcher's publications, balancing publication count against citation depth.

1. What is H-Index Provides a balance between the number of publications and citations received, offering insight into a researcher's overall influence within their field.
   Calculation — Dr. Taylor:
   Top 7 papers received: 12, 10, 8, 6, 5, 4, 2 citations.
   H-Index = 5 — at least 5 papers each cited at least 5 times.

An alternative perspective on researcher impact that gives more weight to highly-cited papers than the h-index does.

1. What is G-Index Captures both quantity and cumulative impact — found at the point where cumulative citations ≥ number of papers squared.
   Calculation — Dr. Smith:
   5 papers with citations: 10, 8, 6, 4, 2
   Top 3 cumulative = 10 + 8 + 6 = 24 citations for 3 papers.
   G-Index = 3

A straightforward metric pioneered by Google Scholar — counting publications that have reached the meaningful threshold of 10 or more citations.

1. What is i10-Index Counts only publications that have garnered a minimum of 10 citations each, providing a succinct measure of academic influence.
   Calculation — Dr. Robert:
   8 papers published in environmental science.
   5 papers received ≥ 10 citations each.
   i10-Index = 5