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The Usefulness of Societies’ Job Listings Data

By
Ronald G. Ehrenberg
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This essay is a response to the declining number of job advertisements in the broader context of the humanities field.

There are many reasons to be cautious when using scholarly societies’ job listings as data about the job market for new PhDs. In addition to those mentioned in the report, they include the fact that academic listings are for all ranks (not just new assistant professors); that the same job may be listed multiple times during a year; that the aggregate numbers tell us nothing about the types of academic jobs listed (tenured, tenure track, full-time nontenure track, part-time nontenure track); and that nonacademic positions may be less frequently listed than academic ones.

Nonetheless, in a forthcoming paper, Jeffrey Groen – an economist at the U.S. Bureau of Labor Statistics and one of the authors of Educating Scholars: Doctoral Education in the Humanities1– presents substantial evidence that societies’ job listings data are useful measures of the demand for new PhD recipients.2 Using up to thirty years’ worth of job listings data for each of seven fields – anthropology, classics, economics, English, history, philosophy, and political science – Groen shows that the movement of these series over time are correlated with a set of variables that plausibly should influence the demand for new PhDs. These correlations include the national unemployment rate (negative), state appropriations per full-time-equivalent student at public academic institutions (positive), expenditures per student at public academic institutions (positive), and average faculty salary levels (positive).

Furthermore, using job outcomes data for new PhD recipients from the Survey of Earned Doctorates, as measured by their responses to a set of questions regarding whether respondents have definite plans for employment or postdoctoral study as of the date of the survey, Groen finds, after controlling for other variables, that job listings measures for the seven disciplines are positively correlated with respondents’ likelihood of having definite plans for employment and postdoctoral study. Together these two types of evidence suggest, in his words, that “the number of job listings is a credible measure of the demand for new doctorate recipients.”

With this established, Groen then estimates whether the demand for new doctorates in the seven fields has any impact on decisions by existing PhD students to complete their degrees in a given year or to continue on in their PhD programs. His estimates suggest that, holding other factors constant, the number of job listings in a field is uncorrelated with both the probability that a student completes his or her PhD and with expected time to degree. He concludes that cyclical variation in labor demand is not responsible for observed changes over time in average times to degree.

Another important issue is whether the number of job listings in a field in a given year has any impact on the number and academic quality of new students who enroll in PhD study in the field. While some impressionistic evidence suggests that top programs in the humanities have shrunk their sizes over time3 in response to worsening job market conditions, the growth of new programs has apparently not led to substantial reductions in overall new PhD program enrollments. And somewhat surprisingly, little formal research has been conducted on whether new PhD program enrollments in a field and the quality of entering PhD students are sensitive to job market conditions. Groen is in the process of using job listings data for the seven fields, as well as other sources, to formally address these questions.

Endnotes

  • 1Ronald G. Ehrenberg, Harriet Zuckerman, Jeffrey A. Groen, and Sharon M. Brucker, Educating Scholars: Doctoral Education in the Humanities (Princeton, NJ: Princeton University Press, 2009).
  • 2Jeffrey A. Groen, “The Impact of Labor Demand on Time to the Doctorate,” Education Finance and Policy, forthcoming. A recent working paper version is available at http://jeffreygroen.weebly.com/uploads/4/2/9/0/42906623/groen_ttd_oct2014.pdf.
  • 3Broad discussions of these issues have been offered by Robert Townsend for history (http://bit.ly/srcZiL) and David Laurence for the Modern Language Association (http://bit.ly/1cOvG4W).
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