Sommersemester 2018

18.04.2018Felix Weinhardt, DIW Berlin
 The Effects of Tuition Fees on Study Duration and Completion in the Population of German Students

This paper estimates the causal effects of fees on the duration of study and completion probabilities for an entire country. The empirical analysis merges difference-in-differences estimation with duration analysis to exploit an unusual natural policy experiment, namely the introduction of fees for university studies in several German states that also applied to enrolled cohorts. Our strategy allows uncovering effects of fees on the intensive margin, while holding constant extensive margin responses such as changes in the composition of the student body or migration responses that occur due to fees. We find that even modest fees have large and significant impacts on study duration and completion rates on students who enrolled before fees were introduced.
25.04.2018Susanne Steffes, Universität zu Köln
 The impact of affirmative action on fairness perception and on-the-job search: evidence from linked employer-employee data

One striking example of gender inequalities in the labor market are substantial gender differences in management positions. In this paper we identify the impact of a firm-level gender quota on behavioral outcomes of employees. We use representative employer-employee survey data to figure out whether the implementation of a gender quota has an impact on the fairness perception and the on-the-job search behavior of men and women. We identify the existence of a gender quota by using the implementation of a law that aims to increase gender equality in management positions in Germany. Our results show a reduction of fairness perception and an increase in turnover intention among men and women. Effects are more pronounced among employees with a higher probability to be affected by the quota. Effects on on-the-job search are only partially explained by affective behavior and might be explained by a shift in outside options.
02.05.2018Dirk Engelmann, Humboldt-Universität Berlin
 Preferences over Taxation of High Income Individuals: Evidence from Online and Laboratory Experiments (with Eckhard Janeba, Lydia Mechtenberg, Nils Wehrhöfer)

Mobility of high income individuals across borders puts pressure on governments to lower taxes. A central tenet of the underlying theoretical and empirical models is that mobile individuals react to tax differentials through migration, and in turn immobile households vote for lower taxes in the face of a migration threat. In light of behavioural economics research it is not clear, however, whether this premise holds. In particular, political ideology might influence voting on taxes. We use an experimental survey design and elicit answers from more than 3,000 households in the German Internet Panel (GIP). We use various treatments to understand the role of mobility and ideology in tax choice. We observe substantial deviations from the predicted theoretical equilibrium. In many cases comparative static results prevail, however. Furthermore, political ideology matters: left-leaning households choose higher taxes than right-leaning persons, and center-right leaning individuals tend to emigrate more when the tax at home is high. We compare the results with those from a closely related lab experiment, in which subjects appear to behave more in line with standard predictions.
09.05.2018Oliver Kirchkamp,  Friedrich-Schiller-Universität Jena
 Conditional cooperation and the effect of punishment (with Wladislaw Mill)

Here we study how punishment interacts with conditional cooperation. We find that punishment increases conditional cooperation. However, we also find a negative effect of punishment: Punishment leads to an increase in the number of free riders. In our study the net effect still is positive. We find two more effects of punishment: Substitution and responsibility. Substitution leads to a decrease in conditional cooperation. Responsibility leads to an increase in conditional cooperation. We find that the overall effect of responsibility is larger.
23.05.2018Roel Leus, KU Leuven
 A model for scheduling with activity failures

An R&D project typically consists of several stages.  Due to technological risks, the project may have to be terminated before completion, each stage having a specific likelihood of success.  In the project planning and scheduling literature, this technological uncertainty has typically been ignored and project plans are developed only for scenarios in which the project succeeds.  In this work we examine how to schedule projects in order to maximize their expected net present value when the project activities have a probability of failure and when an activity’s failure leads to overall project termination.  We describe a general model, develop an exact algorithm and establish a link with stochastic scheduling.
13.06.2018Stephan Heblich, University of Bristol
 East Side Story: Historical Pollution and Persistent Neighborhood Sorting

Why are the east sides of formerly industrial cities often the more deprived? Using individual-level census data together with newly created historical pollution patterns derived from the locations of 5,000 industrial chimneys and an atmospheric model, we show that this results from the persistence of neighborhood sorting that first emerged during the Industrial Revolution when prevailing winds blew pollution eastwards. Past pollution explains up to 20% of the observed neighborhood segregation in 2011, even though coal pollution stopped in the 1970s. A quantitative model identifies the role of non-linearities and tipping-like dynamics underlying this persistence.
20.06.2018Björn Imbierowicz, Deutsche Bundesbank
 Do corporate depositors risk everything for nothing? The importance of deposit relationships, interest rates and bank risk

We analyze more than 75,000 auctions in which banks bid for firm deposits. In each of these auctions, only the firm observes the banks and their bids and decides where to deposit its funds. Our results show that a bank’s risk is irrelevant to firms in their decision, irrespective of its measurement and the economic period. In many cases, firms simply select the highest bidding bank. Our data show that this implies on average the risk of losing €74 million for a maximum higher interest income of only €1,300, that is, 0.18 basis points, compared with the worst bid in the auction. Firms only diversify extraordinarily large deposit amounts but also in this case do not account for the individual banks’ risk. Our findings argue for moral hazard of firms, which seem to rely on government bailouts of banks and/or central bank interventions. We further observe that also in rather impersonal electronic markets, relationships are an important decision criterion for firms. A stronger deposit relationship with a firm increases a bank’s probability to be selected in an auction. Furthermore, it also increases a bank’s access to more unsecured deposits from the firm in future periods, including severe crises. Our results reveal that also in markets with high transparency and no switching costs firms base the decision of where to deposit their money on bank relationships as well as the interest rate, but largely disregard bank risk. This has important implications for banks’ access to unsecured corporate funding.
27.06.2018Stefan Creemers, IÉSEG School of Management
LB 138
Recent advances in project scheduling

In this research seminar, we discuss three recent advances in project scheduling:
1) New benchmark results for the Resource-Constrained Project Scheduling problem (RCPSP).
2) Closed-form results that allow to approximate the distribution and to determine the moments of the net present value (NPV) of a project.
3) A new Continuous-Time Markov Chain (CTMC) that can be used to schedule the activities of a Markovian PERT network.

The RCPSP is one of the most well-known problems in the OR literature. The goal of the RCPSP is to schedule a set of activities, while satisfying precedence and resource constraints, such that the project makespan is minimized. The current state-of-the-art solution methods use branch-and-bound procedures or MILP formulations/solvers. However, since the RCPSP is NP-hard, these exact methods are unable to find optimal schedules for projects that have 60 or more activities. In this seminar, we present new procedures that allow to solve several, previously unsolved, problem instances.

Next to minimizing the makespan of a project, maximizing its NPV is another important objective. Since it is NP-hard to determine even a single point of the distribution of the NPV, most researchers have focused their efforts on trying to maximize the expected NPV (eNPV) of a project. Higher moments and/or the NPV distribution itself had to be approximated using Monte Carlo simulation. In this seminar, we present exact, closed-form expressions for the moments of the NPV, and develop a highly accurate closed-form approximation of the NPV distribution itself.

If project activities have exponentially-distributed durations, the project is also referred to as a Markovian PERT network. Until recently, all work on the scheduling of Markovian PERT networks has used the CTMC of Kulkarni and Adlakha (Operations Research, 1986). In this seminar, we present a new CTMC that drastically reduces memory requirements, and propose a new and efficient approach to structure the state space of the CTMC. The new CTMC allows us to easily outperform existing procedures for scheduling Markovian PERT networks.
04.07.2018Jeanne Hagenbach, Sciences Po Paris
 Communication with Evidence in the Lab (with Eduardo Perez-Richet)

We study a class of sender-receiver disclosure games in the lab. Our experiment relies on a graphical representation of sender's incentives in these games, and permits partial disclosure. We use local and global properties of the incentive graph to explain behavior and performance of players across different games. Sender types whose interests are aligned with those of the receiver fully disclose, while other types use vague messages. Receivers take the evidence disclosed by senders into account, and perform better in games with an acyclic graph. Senders perform better in games with a cyclic graph. The data is largely consistent with a non-equilibrium model of strategic thinking based on the iterated elimination of obviously dominated strategies.
11.07.2018Julia Müller (Westfälische Wilhelms-Universität Münster)
 Can Money make you clever? Performance at Intellectual Work (with Thomas Apolte)

Performance can often be improved by providing monetary incentives. Do incentives only work for rather simple tasks involving effort or also for tasks involving intellectual endeavours? In order to answer this question we performed an experiment using the Wason selection task. In the experiment we implement different kinds of
incentives and and heterogeneous effects of the incentives. Only high individual incentives are able to slightly improve performance, while lower individual incentives and group incentives show no eect on performance.
18.07.2018Hannah Schildberg-Hörisch, DICE
 Who should (not) benefit from affirmative action? Ability, effort, and discrimination as justifications for affirmative action (with Chi Trieu and Jana Willrodt)

Affirmative action policies favor members of a group that is perceived as disadvantaged. Since it was first introduced in 1964, affirmative action has been a subject of heated debates. The underlying conflict in this debate is the collision of different fairness ideals that differ with respect to which factors individuals are held responsible for when judging their performance. While libertarians deny the necessity of affirmative action altogether, meritocracists support affirmative action compensating for impersonal factors such as bad luck or discrimination. Choice egalitarianism favors affirmative action offsetting the impact of factors out of one’s control such as bad luck or innate ability but not endogenously chosen effort provision. Finally, strict egalitarianism strives for counterbalancing differences in all factors determining performance, namely bad luck, productivity and effort.

In a laboratory experiment, we study three types of affirmative action schemes that introduce quota for bad luck (i.e. discriminated), low ability or low effort individuals, respectively. We then examine outcomes of affirmative action in a tournament context, and investigate both immediate outcomes (efficiency / average performance and willingness to compete), post-tournament outcomes (cooperation within a team, and spiteful behaviors targeting individuals favored by affirmative action) as well as fairness perceptions of the various affirmative action schemes.

To the best of our knowledge, our study is the first to study consequences of affirmative action schemes related to low ability and low effort provision as well as to systematically compare affirmative action schemes based on bad luck / discrimination, effort, and ability in a unified framework. Moreover, we provide first evidence on heterogeneity in perceived fairness of the various affirmative action schemes.