Abstracts Category : Other

Modeling Approaches in Educational Research

by Tim Ehlers

This dissertation focuses on three different questions in the field of education, using the method of theoretical modeling. The subject discussed first refers to the existence of tuition fees. If the personal question of going to a university or not to enroll is a rational decision based on financial advantage, tuition fees are hard to convey when they do not provide a surplus in the form of better study conditions. In contrast, tuition fees may become attractive if a university degree in addition yields a non-monetary value in terms of status or reputation. The basic assumption is that prestige rises when the number of people studying decreases. Then, one might want to minimize the enrollment rate by all possible means to maximize the reputational effect. This dissertation presents a model based on this effect where in a static equilibrium wealthier and more able students vote for higher tuition fees just to detain others from studying.In the next field focused, a concern for reputation is introduced into an established signaling model of grading. It is called Grade inflation, when grades lose their informative value because the percentage of students receiving the best grade rises without any corresponding increase in ability. Conventional wisdom says that such grade inflation is unavoidable since it is essentially costless to award good grades. Here an effect driving into the opposite direction is shown: Grade inflation is not actually costless, since it has an impact on future cohorts of graduates, or, put differently, by grading honestly, a school can build up reputation. The enhanced model shows that this mechanism reduces or even avoids grade inflation.In the final chapter, a theory is presented explaining the impact of ability tracking on academic performance based on grading policies. The model distinguishes between initial ability, which is mainly determined by parental background, and eagerness to learn. It is shown that achievements of low ability students may be higher in a comprehensive school system, even if there are no synergy effects from teaching different students together. This arises because the comprehensive school sets a compromise standard which exceeds the standard from the low ability track. Moreover, if students with lower initial ability have higher eagerness to learn, merging classes will increase average performance.Advisors/Committee Members: Schwager, Robert (advisor), Schwager, Robert (referee), Rbel, Gerhard (referee).