Comments and Questions

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 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.