Fast track or failure: a study of the graduation and dropout rates of Ph D students in economics

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Abstract

We analyze the production process of Ph Ds in economics in The Netherlands. Our empirical results are consistent with the incentives that the actors in this process face. Universities succeed in making students who are unlikely to graduate or will need a long time to graduate quit the program. We find that supervisors who are active researchers have higher graduation and lower dropout rates. However, this effect is due to the fact that supervisors with a good research record have better students. There is no evidence of an independent effect of having a supervisor who is an active researcher.

Introduction

This paper is a contribution to the small empirical literature on the Ph D production process. As is common in that literature, we relate the input of students to the output of graduates. This relationship is determined by the attrition of students from the graduate program and the time that students who stay in the program need to complete their doctoral thesis. Attrition and completion are affected by choices made by the students. However, the thesis supervisor, the department, and even the university are also actors in the Ph D production process. Breneman (1976) proposed a model for the decisions of the actors, given their preferences and the restrictions that they face. We adapt his model that was formulated for the US, to the conditions in a small European country, c.q. the Netherlands.

Most of the empirical literature has focused on differences in attrition and completion rates between fields and on the effect of financial support on these rates. Because we concentrate on a particular discipline, and all doctoral students essentially have the same generous financial support, we consider other factors. We show that in The Netherlands students who are supervised by active researchers have a lower attrition rate and a higher completion rate. However, this is not due to the quality of the supervision provided by active researchers, but to the higher quality of the students that they attract and select. This result is consistent with the incentives (or the lack thereof) faced by supervisors. Hence, our results are in line with those of Breneman (1976) who concludes that the actors in the Ph D production process are sensitive to incentives.

Our study provides an interesting contrast to studies of Ph D programs in Anglo-Saxon countries, which are the only programs that have been the subject of empirical research. We give a brief survey of that research. Bowen and Rudenstine (1992) study graduate students in six fields at ten major research universities in the US over a 25-year period. They show that completion rates depend on the type of financial support that the students receive. Booth and Satchell (1995) analyze retrospective information, collected in 1986, on 500 students who entered (in 1980) a British Ph D program in the social sciences, arts and languages, or science and engineering. They find that neither financial support from the research council nor student quality, as measured by undergraduate scores, have a significant effect on the completion rate. A variable that does influence thesis completion is the subject area, with arts and languages having lower and science and engineering having higher completion rates than the social sciences.1 Ehrenberg and Mavros (1995) use data on entrants during 1962–1986 in Cornell University’s doctoral programs in economics, English, physics and mathematics. Following Breneman (1976), they consider the effect of labor market conditions on the attrition and completion rates. Ehrenberg and Mavros find that completion rates decrease with time spent as a teaching assistant. Dropout rates are lower if, at the start of the program, a Ph D student had a master’s degree or was not a US citizen or permanent resident. Student quality and labor market conditions do not have a significant effect on the completion and dropout rates. The authors note that this may be due to the inadequacy of the student ability measures and the labor market indicators.

We use data on Ph D students in economics at three Dutch universities that have a joint doctoral program. The data are obtained from administrative files, so that we only have a small number of student and supervisor characteristics.

Beside the substantial contributions to the understanding of the Ph D production process, this paper makes two econometric contributions. First, we show how to estimate the risk of an outcome, even if that outcome is never observed. Second, we test for endogeneity of a regressor in a rather complex competing risks model.

The paper is organized as follows. In Section 2 we discuss the Ph D program in economics in The Netherlands and the incentives that students, supervisors and departments face in this program. The data that we use in our analysis are described in Section 3. Section 4 discusses the statistical model and Section 5 presents the estimation results. Section 6 discusses some implications of our results.

Section snippets

The Ph D production process

The graduate program in the Netherlands has undergone a major overhaul in the late 1980s. Before the overhaul universities recruited junior faculty from the ranks of the MA graduates. Undergraduate education in The Netherlands is highly specialized, and at the time an undergraduate degree was about equivalent to an MA degree in the US. In addition to teaching, the junior faculty worked on their dissertation, which they eventually did or did not complete. The supervision of this dissertation

Data

From the administrative files of three Dutch universities we derived information concerning characteristics of the Ph D students and their supervisors. In our analysis we use information on 250 Ph D students who started before January 1, 1993. The closing date of our administrative files is January 1, 1998. After removing Ph D students who had a foreign9

Statistical model

Our statistical model is similar to the competing risks model used by Ehrenberg and Mavros (1995). We assume that a Ph D student faces two ‘risks’: one of completing the Ph D, the other of dropping out. We investigate several alternative specifications. We start with a competing risks model in which, conditionally on the observed regressors, both transition rates are independent. Next, we allow for dependence between the risks by introducing unobserved differences between the students. We

Estimation results

The estimation results are given in Table 3. The first column shows the results for the competing risks model without unobserved heterogeneity. Students who have a degree from their supervisor’s university have a significantly higher graduation rate. The same is true for students who obtained their undergraduate degree in less than five years. There is significant duration dependence in the completion rate with the rate being lowest in the fourth year, higher from four to six years, and

Conclusions

This paper presents an analysis of the production process of Ph Ds in economics at three universities in The Netherlands. We find that students who are likely to take a long time to graduate are also more likely to drop out. The university and the department succeed in making these students quit the program. However, this attrition occurs over the full four years of the contract and even after the end of the contract. It would be preferable to introduce a more stringent evaluation; for example,

Acknowledgements

We thank the associate editor for excellent suggestions that helped us to focus the paper.

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