Discussion Paper

No. 2015-31 | April 23, 2015
On the Size of Sheepskin Effects: A Meta-Analysis
(Published in Special Issue Meta-Analysis in Theory and Practice)


The authors use information gathered from 122 studies on the effects of high school diplomas on wages in different countries worldwide to carry out a meta-analysis that shows high school diplomas have a statistically significant effect on wages of nearly 8 percent. This effect varies whether the country is away from the tropics or whether factors such as sex, race, and continent are taken into account. The authors’ results also reveal the existence of a publication bias that tends to increase the magnitude of the sheepskin effect. Nevertheless, when the former is factored into the analysis the latter remains statistically significant.

JEL Classification:

C8, I21, J24


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Cite As

Jhon James Mora Rodríguez and Juan Muro (2015). On the Size of Sheepskin Effects: A Meta-Analysis. Economics Discussion Papers, No 2015-31, Kiel Institute for the World Economy. http://www.economics-ejournal.org/economics/discussionpapers/2015-31

Comments and Questions

Anonymous - Referee Report 1
May 05, 2015 - 09:48

see attached file

Jhon James Mora Rodríguez and Juan Muro - Reply to Referee Report 1
May 18, 2015 - 12:29

see attached file

Anonymous - Referee Report 2
June 12, 2015 - 16:39

The topic is interesting and it is useful to use a meta regression analysis (MRA) to determine the average size of the effect and whether there is any publication bias.
In general, the grammar, in text referencing and presentation of material are poor.
Specifically, it would be useful to use ...[more]

... some of the Introduction and Section 2 to explain the sheepskin effect with reference to the seminal work of Layard and Psacharopoulos (1974). The literature review is weak and there is no mention of which keywords were used in the search reported in section 3. In addition, it is unusual for all studies found in the first search to be used in the subsequent meta-analysis. More usually, MRAs refer to the number of studies that are found initially, then why some of these are not subsequently used. Thus, were only 122 articles found or were only 122 of the found articles useful for the MRA? Author(s) and years of the included articles and their key parameters should be listed in an Appendix. Are these MRA data available on the Deakin University repository or other website?
An argument for the obsolescence of the sheepskin effect is not given (section 4).
There is no mention of the Stanley et al. (2013) guidelines for the conduct of MRA. In particular, the MRA dataset should be coded by two people.
Some of the references are dated. See more recent studies reporting wage equations, MRA and publication bias.

Jhon James Mora Rodríguez and Juan Muro - Reply to Referee Report 2
June 24, 2015 - 09:12

see attached file