by Erin Prentiss
Measuring scholarly productivity is of critical importance to faculty but is a subject of much debate. One tool that has been developed is the h-index. In the decade since it was proposed by physicist Jorge E. Hirsch, the h-index has become a standard metric of scholarly productivity. Hirsch (2005) developed the h-index to provide “an estimate of the importance, significance, and broad impact of a scientist’s cumulative research contributions” (p. 16569). The h-index accomplishes this by taking into account both the number of papers a researcher has published and the number of times these papers have been cited in other publications. According to Hirsch (2005), “a scientist has index h if h of his or her Np [Np = number of papers] papers have at least h citations each and the other (Np – h) papers have ≤h citations each” (p. 16569). Therefore, a large h-index value indicates a scholar who is both a very prolific and highly cited author.
As an example of calculating an h-index, say that M.Y. Reese-Ersch has published ten papers. The ten papers have been cited 20, 25, 20, 10, 5, 1, 1, 1, 1, and 1 times respectively. Integrating these numbers into the formula, Reese-Ersch will have an h-index of 5 because out of her 10 papers, 5 have at least 5 citations each.
Manually calculating an h-index can be intimidating, but fortunately, there are tools that calculate the h-index. Publish or Perish is a freely downloadable software program that pulls its data from Google Scholar and Microsoft Academic Search. The h-index can also be calculated using Web of Science , which is available on the Health Sciences campus. For more information on how to calculate your h-index with these services, read the 2-minute “Introduction to PoP Author Search” or watch the Web of Science Citation Report training video. Please note that you may get different h-index values based on which tool you use due to the limitations of the databases from which each h-index program draws its author and citation data.
It is important to keep in mind that, as with any other scholarly productivity metric, the h-index has its advantages and disadvantages. One major advantage to the h-index is that it has been found to be more reliable than “single number criteria commonly used to evaluate the scientific output of a researcher [like] impact index, total number of documents, total number of citations, citation per paper rate and number of highly cited papers” (Alonso, Cabrerizo, Herrera-Viedma, & Herrera, 2009, p. 275). Disadvantages to the h-index include a failure to give highly cited articles more weight relative to their importance, which can result in “researchers with some extremely cited papers [having] a similar or equal h-index as researchers with moderate or high cited papers” (Alonso et al., 2009, p. 276). Conversely, the h-index can also privilege recognized authorities in their fields by producing higher h-index numbers for them because those authorities’ “works are cited disproportionately more often than those that are less widely known” (Alonso et al., 2009, p. 276). Additionally, early career researchers are at a disadvantage with the h-index because they have not been in the field long enough to generate enough publications to achieve a high h-index value (Alonso et al., 2009).
If you have questions about the h-index or other measures of scholarly productivity, please contact Kim Mears, Scholarly Communications Librarian at firstname.lastname@example.org or 706-721-8789.
Alonso, S., Cabrerizo, F., Herrera-Viedma, E., & Herrera, F. (2009). h-Index: A review focused in its variants, computation and standardization for different scientific fields. Journal of Infometrics, 3(4), 273-289. doi:10.1016/j.joi.2009.04.001
Hirsch, J. E. (2005). An index to quantify an individual’s scientific research output. Proceedings of the National Academy of Sciences of the United States of America, 102(46), 16569-16572. doi:10.1073/pnas.0507655102