In 2005 Jorge Hirsch proposed, “An Index To Quantify an Individual’s Scientific Research Output,” commonly known as the Hirsch Index, denoted by h. The Hirsch Index measures the largest number h for which a researcher has a least h papers with at least h citations each.
In 2013, Glenn Ellison developed a modified Hirsch Index for the field of economics because, “economists write fewer papers than do physicists, and individual papers get many citations. As a result, the h index is uncomfortably like a publication count.” To illustrate, Ellison notes that Roger Myerson, who received the 2007 Nobel Prize in Economics, has an h-index of 44 based on Google Scholar citations, which is smaller than the h-index for most AAEA Fellows. Ellison illustrates the weakness of the h-index for economics: “the profession cares much more about the several tremendously important papers Myerson has written than it does about whether his forty-fourth most-cited paper has as many citations as someone else’s 44th most-cited paper.”
To address the weakness of the h-index for economics, Ellison suggests “raising the standard for what ‘good’ means, so that the index focuses on a smaller number of papers.” He proposes a variant of the Hirsch index, , that is the largest h for which a researcher has at least h papers with at least citations each. I refer to this index as the Hirsh-Ellison Index, he-index.
To determine the right values for a and b, Ellison estimates the parameters that best explain job market outcomes. He provides two sets of parameters. One set, a=15 and b=3, is optimal when each coauthor on a paper receives credit for 1/n of the paper, where n is the number of coauthors. The optimal parameter values are a=10 and b=3 when the co-author weighting is estimated jointly with a and b; the market appears to give coauthors credit for papers.
To facilitate comparison of scholars of different “vintage,” Ellison estimates an optimal age adjustment.
The following table reports the he-index for tenured and near-tenured faculty in the department of Agricultural and Consumer Economics at the University of Illinois at Urbana-Champaign, my department.
Ellison, Glenn. 2013. “How Does the Market Use Citation Data? The Hirsch Index in Economics.” American Economic Journal: Applied Economics 5 (3): 63–90.
Hirsch, Jorge 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.