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Auctions with endogenous rationing have been introduced to stimulate competition. Such (procurement) auctions reduce the volume put out to tender when competition is low. This paper finds a strong negative effect of endogenous rationing on participation when bid-preparation is costly, counteracting the aim to stimulate competition. For multiple auctioneer's objectives mentioned in directives, we derive optimal mechanisms, which differ due to different evaluation of the tradeoff between participation and bid-preparation costs. Thus, the auctioneer needs to decide on an objective. However, reducing bid-preparation costs improves the optimal values of multiple objective functions.

In verschiedenen Ländern wie z.B. Deutschland und Frankreich wurde in den jüngsten Ausschreibungsrunden für den Bau neuer Windenergieanlagen an Land die Ausschreibungsmenge von der Angebotsmenge nicht oder nur knapp überschritten. Diese Entwicklung in Verbindung mit geplanten Sonderausschreibungen erhöht die Risiken zukünftiger Unterzeichnungen und hoher Preise. Zur Lösung dieses Problems in Deutschland wird von verschiedenen Stellen wie der Bundesregierung vorgeschlagen, Instrumente der endogenen Rationierung in das Auktionsdesign zu implementieren. Konkret schlägt § 11 Absatz 2 InnAusV der „Verordnung zu den Innovationsausschreibungen und zur Änderung weiterer energiewirtschaftlicher Verordnungen“ vom 16. Oktober 2019 (Bundesregierung, 2019a) eine Auktion mit sogenannter endogener Rationierung vor. Die Instrumente der endogenen Rationierung sollen im Fall eines zu geringen oder zu teuren Angebots das Ausschreibungsergebnis anpassen, indem das Zuschlagsvolumen in Abhängigkeit vom Angebotsvolumen bzw. von den Gebotspreisen reduziert wird. Dadurch sollen Wettbewerb in den Ausschreibungsrunden und niedrigere Preise gesichert werden.

This paper derives Bayesian equilibria under general conditions for a broad family of sealed-bid combinatorial auction formats under incomplete information. Equilibria are constructed by linking an equilibrium of the combinatorial auction format to an equilibrium of its single-unit version, thereby providing a closed-form expression if the single-unit version has one. Auction formats that share the same single-unit version, like the Vickrey auction and all bidder-optimal core-selecting auctions, have common equilibria for any number of items and bidders. Furthermore, if an ex-post equilibrium exists in the single-unit version of an auction then the auction format has an ex-post equilibrium in the combinatorial auction. We characterize the ex-post equilibria for a subfamily of auctions.

We investigate equilibrium bidding behavior of bidders with reference-dependent preferences and independent private values in single-unit English and Dutch clock auctions. Bidders' reference points are endogenous and determined by their strategy and their beliefs about the other bidders. In deriving their strategy, bidders anticipate changes in their reference point due to updated information about others' values (i.e., the own winning probability) during the course of the auction, and make optimal binary decisions at each price (approve or quit in the English auction and wait or bid in the Dutch auction). First, we solve for personal equilibrium profiles, i.e., profiles of bids that contain for each bidder a bidding strategy that is optimal given the others' bidding strategies and the reference point induced by the own and others' strategies. Second, we consider locally preferred personal equilibrium (LPPE) profiles, i.e., personal equilibrium profiles where no bidder can locally find a better personal equilibrium given the others' fixed strategies by varying his reference point via considering different own strategies. The expected revenue in the Dutch auction is higher than in the English auction in the respective unique LPPE profiles. The difference is mainly driven by the aversion to losing the item in the Dutch auction.

We find new equilibria of minimum-revenue core-selecting (MRCS) auctions that, in contrast to previously identified equilibria, involve overbidding - bidding more than one's true value for some packages of goods. With full information, every MRCS auction in every possible setting has equilibria with overbidding and these equilibria have different properties than the previously known equilibria with bid shading. Namely, they can lead to strictly higher revenues for the seller and larger price differences among bidders. Previous studies of MRCS games with incomplete information assumed restricted strategy spaces that prevented overbidding. In this paper, we allow bidders access to their complete strategy sets and show that, in some settings, overbidding occurs in all Bayesian equilibria in undominated strategies. In a simple setting with independent private values, equilibrium strategies of a particular set of MRCS auctions employ a mixture of bid shading and overbidding. These new equilibria improve expected effi ciency relative to equilibria with restricted strategy spaces and lead to higher expected revenues than those from the Vickrey package auction. A second incomplete-information setting demonstrates that equilibria with overbidding can be in some sense unique. In this setting, every Bayesian equilibrium in undominated strategies of every MRCS auction has at least one bidder who overbids and there is no bid shading on winning packages. Overbidding eliminates the threshold problem, leading to an effi cient assignment and payoffs that are in the core with respect to the true values.

Frankfurt am Main 2012, 44 S., Der Forschungsbericht bezieht sich auf eine ethnographische Studie in Mutter-Kind-Einrichtungen des Strafvollzugs. Diese Einrichtungen kennzeichnet eine doppelte Organisationsform, da sie zugleich Strafvollzugs- und Jugendhilfeeinrichtungen sind. Im Fokus der Fragestellung standen die Entwicklungsbedingungen der Kinder und die Frage, wie die Zuständigkeiten für die Kinder zwischen Müttern, Erzieherinnen, Sozialarbeiter/-innen und Vollzugspersonal organisiert werden. Die Studie zeigt, dass durch die doppelte Organisationsform Konfliktpotenziale zwischen dem Ziel der Sozialisation der Kinder und dem der Resozialisation der Mütter entstehen und dass dabei die Beobachtungs- und Kontrollformen der Haftanstalt und der Jugendhilfeeinrichtungen untrennbar verwoben werden. Um in eine Mutter-Kind-Einrichtung des Strafvollzugs aufgenommen zu werden, werden den straffälligen Müttern grundsätzlich Erziehungsfähigkeiten zugeschrieben, die Ausübung ihrer Erziehungspflichten ist allerdings durch die Haftbedingungen eingeschränkt und muss daher durch das pädagogische Personal kompensiert werden. Im Alltag der Einrichtungen führt dies dazu, dass strukturell angelegte Konflikte um gelingende Mutterschaft und die Sicherung des Kindeswohls häufig auf der persönlichen Ebene zwischen Erzieherinnen und Müttern zu verhandeln und auszutragen sind. Der Forschungsbericht beschreibt Konflikte und Konfliktpotenziale solcher Einrichtungen und geht auf die Bedingungen der Mutterschaft in Haft sowie die organisierte Lebenssituation der Mitinhaftierung der Kinder ein. (DIPF/Autor)

Die Septische Granulomatose (CGD) ist eine seltene Erkrankung, die auf einem genetischen Defekt bestimmter weißer Blutzellen beruht, die darauf spezialisiert sind, in den Körper eingedrungene Pilze und Bakterien aufzuspüren und zu vernichten. Frankfurter Ärzten und Wissenschaftlern um Prof. Dr. Dieter Hoelzer vom Klinikum der Johann Wolfgang Goethe-Universität und Dr. Manuel Grez vom Chemotherapeutischen Forschungsinstitut Georg-Speyer-Haus gelang es, eine intakte Kopie des defekten Gens in Blutstammzellen von zwei erwachsenen CGD-Patienten einzuschleusen und so die Funktion der Fresszellen teilweise wieder herzustellen. Eine vollständige Heilung gelang jedoch nicht – ein Patient verstarb zwei Jahre nach der zunächst erfolgreichen Behandlung an seiner Grunderkrankung. Im Gespräch mit Dr. Anne Hardy berichten Dr. Marion Gabriele Ott (Arbeitsgruppe Hoelzer) und Dr. Manuel Grez (Georg-Speyer-Haus) über die Höhen und Tiefen ihrer gentherapeutischen Forschung.

We analyze a model of Internet auctions. Sellers each offer one item of a heterogeneous good to bidders who have unit-demand preferences. Items are sold in second-price proxy auctions. We derive a perfect Bayesian (epsilon-) equilibrium. Our experimental findings support the theoretical results. An analysis of sellers' revenues in the Vickrey-auction reveals that they are non-monotonic in bids for substitutes valuations. We combine these results to investigate incomplete bidder-seller networks.

It is not a secret that certain auction formats yield on average higher prices than others. The phenomenon that dynamic auctions are more likely to elicit higher bids than static one-shot auctions is often associated with the term ''auction fever.'' On a psychological level, we consider the so-called pseudo-endowment effect as largely responsible for peoples’ tendency to submit higher bids, potentially amplified by the source-dependence effect. The phenomenon of auction fever is replicated in an experimental investigation of different auction formats within a private values framework where bidders have private but incomplete knowledge of their valuation for a hypothetical good. We suggest this assumption to be more realistic than definite private values, as assumed in the traditional IPV model. An additional experimental investigation within the traditional IPV framework does not either reveal any indication for the appearance of auction fever. On the basis of our experimental observations we present a model of reference-dependent utility theory that comprehends the phenomenon by assuming that bidders' reference points are shifted by the pseudo-endowment and the source-dependence effect.

A population of players is considered in which each agent can select her neighbors in order to play a 2x2 Hawk-Dove game with each of them. We design our experiment in continuous time where participants may change their Hawk-Dove action and/or their neighborhood at any point in time. We are interested in the resulting formation of networks and the action distributions. Compared with static Nash equilibrium (e.g., Berninghaus and Vogt, 2004, 2006; Bramoulle, Lopez-Pintado, Goyal, and Vega-Redondo, 2004) and social optimum as theoretical benchmark solutions, subjects seem to employ a more complex, forward-looking thinking. We develop an other benchmark solution, called one-step-ahead stability, that combines forward-looking belief formation with rational response and that fits the data much better.

A population of players is considered in which each agent can select her neighbors in order to play a 2x2 Hawk-Dove game with each of them. We design our experiment in continuous time where participants may change their Hawk-Dove action and/or their neighborhood at any point in time. We are interested in the resulting formation of networks and the action distributions. Compared with static Nash equilibrium (e.g., Berninghaus and Vogt, 2004, 2006; Bramoulle, Lopez-Pintado, Goyal, and Vega-Redondo, 2004) and social optimum as theoretical benchmark solutions, subjects seem to employ a more complex, forward-looking thinking. We develop an other benchmark solution, called one-step-ahead stability, that combines forward-looking belief formation with rational response and that fits the data much better.

In recent work on non-cooperative network formation star-shaped networks play an important role. In a particular theoretical model of Bala and Goyal (2000) center-sponsored stars are the only strict Nash networks. In testing this theoretical model Falk and Kosfeld (2003) do not find any experimental evidence that players select the center-sponsored star. Based on a slight modification of Bala and Goyal's model we design a network formation experiment with varying link costs in which almost all groups not only reach a strict Nash network once but also switch strict Nash networks several times. The main innovation in our experiment is to use a continuous time framework which makes coordination on "stars" much easier than simultaneous strategy adaptation in discrete time.

In an experimental framework on network formation inspired by the two-way information flow model of Bala and Goyal (2000), we observe that many groups participating in the experiment reach the strict Nash network resp. come very close to this network. Compared to the results of previous network experiments this is new. Among other things, the role of inequity aversion in explaining our experimental results is discussed.

Inspired by the theoretical results on network formation by Bala and Goyal (2000) and experimental evidence by Plott and Callander (2002) and Falk and Kosfeld (2003) we design network formation experiments in discrete and continuous time. Particularly in the continuous time experiment, we observe that many groups not only reach a strict Nash network but also switch to other strict Nash networks during the course of time. Strict Nash networks, therefore, prove to be a good indicator for predicting network formation. In explaining our results, we highlight the role of the complexity of network structures, of inequity aversion, and the players� activity levels as most important determinants for forming strict Nash networks.

In an experimental framework on network formation inspired by the two-way information flow model of Bala and Goyal (2000), we observe that many groups participating in the experiment reach the strict Nash network resp. come very close to this network. Compared to the results of previous network experiments this is new. Among other things, the role of inequity aversion in explaining our experimental results is discussed.

Auctions have been developed for economic transactions with asymmetric information and they are the simplest means of price determination for multilateral trading without "market makers." During the last years, new technologies gave a boost to the development and usage of innovative auction formats in several fields. We explore some of the new possibilities of applications and explain the differences to traditional auction formats. Furthermore, we demonstrate the potentialities of auctions concerning information gaining for the auctioneer as well as for the participating bidders.

Auctions have been developed for economic transactions with asymmetric information and they are the simplest means of price determination for multilateral trading without �market makers.� During the last years, new technologies gave a boost to the development and usage of innovative auction formats in several fields. We explore some of the new possibilities of applications and explain the differences to traditional auction formats. Furthermore, we demonstrate the potentialities of auctions concerning information gaining for the auctioneer as well as for the participating bidders.