Publications of Attila Ambrus
%% Journal Articles
@article{fds237863,
Author = {Ambrus, A},
Title = {Coalitional rationalizability},
Journal = {Quarterly Journal of Economics},
Volume = {121},
Number = {3},
Pages = {903-929},
Publisher = {Oxford University Press (OUP)},
Year = {2006},
Month = {August},
ISSN = {0033-5533},
Abstract = {This paper investigates how groups or coalitions of players
can act in their collective interest in noncooperative
normal form games even if equilibrium play is not assumed.
The main idea is that each member of a coalition will
confine play to a subset of their strategies if it is in
their mutual interest to do so. An iterative procedure of
restrictions is used to define a noncooperative solution
concept, the set of coalitionally rationalizable strategies.
The procedure is analogous to iterative deletion of never
best response strategies, but operates on implicit
agreements by different coalitions. The solution set is a
nonempty subset of the rationalizable strategies. © 2006 by
the President and Fellows of Harvard College and the
Massachusetts Institute of Technology.},
Doi = {10.1162/qjec.121.3.903},
Key = {fds237863}
}
@article{fds237862,
Author = {Ambrus, A and Takahashi, S},
Title = {Multi-sender cheap talk with restricted state
spaces},
Journal = {Theoretical Economics},
Volume = {3},
Number = {1},
Pages = {1-27},
Year = {2008},
Month = {March},
ISSN = {1555-7561},
Abstract = {This paper analyzes multi-sender cheap talk when the state
space might be restricted, either because the policy space
is restricted or the set of rationalizable policies of the
receiver is not the whole space. We provide a necessary and
sufficient condition for the existence of a fully-revealing
perfect Bayesian equilibrium for any state space. We show
that if biases are large enough and are not in similar
directions, where the notion of similarity depends on the
shape of the state space, then there is no fully-revealing
perfect Bayesian equilibrium. The results suggest that
boundedness, as opposed to dimensionality, of the state
space plays an important role in determining the qualitative
implications of a cheap talk model. We also investigate
equilibria that satisfy a robustness property diagonal
continuity. Copyright © 2008 Attila Ambrus and Satoru
Takahashi.},
Key = {fds237862}
}
@article{fds237859,
Author = {Field, E and Ambrus, A},
Title = {Early marriage, age of menarche, and female schooling
attainment in Bangladesh},
Journal = {Journal of Political Economy},
Volume = {116},
Number = {5},
Pages = {881-891},
Publisher = {University of Chicago Press},
Year = {2008},
Month = {October},
ISSN = {0022-3808},
Abstract = {Using data from rural Bangladesh, we explore the hypothesis
that women attain less schooling as a result of social and
financial pressure to marry young. We isolate the causal
effect of marriage timing using age of menarche as an
instrumental variable. Our results indicate that each
additional year that marriage is delayed is associated with
0.22 additional year of schooling and 5.6 percent higher
literacy. Delayed marriage is also associated with an
increase in use of preventive health services. In the
context of competitive marriage markets, we use the above
results to obtain estimates of the change in equilibrium
female education that would arise from introducing age of
consent laws. © 2008 by The University of Chicago. All
rights reserved.},
Doi = {10.1086/593333},
Key = {fds237859}
}
@article{fds237858,
Author = {Ambrus, A and Weinstein, J},
Title = {Price dispersion and loss leaders},
Journal = {Theoretical Economics},
Volume = {3},
Number = {4},
Pages = {525-537},
Year = {2008},
Month = {December},
ISSN = {1555-7561},
Abstract = {Dispersion in retail prices of identical goods is
inconsistent with the standard model of price competition
among identical firms, which predicts that all prices will
be driven down to cost. One common explanation for such
dispersion is the use of a loss-leader strategy, in which a
firm prices one good below cost in order to attract a higher
customer volume for profitable goods. By assuming each
consumer is forced to buy all desired goods at a single
firm, we create the possibility of an effective loss-leader
strategy. We find that such a strategy cannot occur in
equilibrium if individual demands are inelastic, or if
demands are diversely distributed. We further show that
equilibrium loss leaders can occur (and can result in
positive profits) if there are demand complementarities, but
only with delicate relationships among the preferences of
all consumers. Copyright © 2008 Attila Ambrus and Jonathan
Weinstein.},
Key = {fds237858}
}
@article{fds237860,
Author = {Ambrus, A and Argenziano, R},
Title = {Asymmetric networks in two-sided markets},
Journal = {American Economic Journal: Microeconomics},
Volume = {1},
Number = {1},
Pages = {17-52},
Publisher = {American Economic Association},
Year = {2009},
Month = {February},
ISSN = {1945-7669},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000284507300002&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {This paper investigates pricing decisions and network
choices in twosided markets with network externalities.
Consumers are heterogeneous in how much they value the
externality. Imposing restrictions on the extent of
coordination failure among consumers generates clear
qualitative conclusions about equilibrium market
configurations. Multiple asymmetric networks can coexist in
equilibrium, both in the case of a monopolist network
provider and in the case of competing providers. These
equilibria have the property that one network is cheaper and
larger on one side, while the other network is cheaper and
larger on the other side. Product differentiation is
endogenized by consumers' network choices.},
Doi = {10.1257/mic.1.1.17},
Key = {fds237860}
}
@article{fds237861,
Author = {Ambrus, A},
Title = {Theories of coalitional rationality},
Journal = {Journal of Economic Theory},
Volume = {144},
Number = {2},
Pages = {676-695},
Publisher = {Elsevier BV},
Year = {2009},
Month = {March},
ISSN = {0022-0531},
Abstract = {This paper generalizes the concept of best response to
coalitions of players and offers epistemic definitions of
coalitional rationalizability in normal form games. The
(best) response of a coalition is defined to be an operator
from sets of conjectures to sets of strategies. A strategy
is epistemic coalitionally rationalizable if it is
consistent with rationality and common certainty that every
coalition is rational. A characterization of this solution
set is provided for operators satisfying four basic
properties. Special attention is devoted to an operator that
leads to a solution concept that is generically equivalent
to the iteratively defined concept of coalitional
rationalizability. © 2008 Elsevier Inc. All rights
reserved.},
Doi = {10.1016/j.jet.2007.03.010},
Key = {fds237861}
}
@article{fds237857,
Author = {Ambrus, A and Field, E and Torero, M},
Title = {Muslim family law, prenuptial agreements, and the emergence
of dowry in Bangladesh},
Journal = {Quarterly Journal of Economics},
Volume = {125},
Number = {3},
Pages = {1349-1397},
Publisher = {Oxford University Press (OUP)},
Year = {2010},
Month = {August},
ISSN = {0033-5533},
Abstract = {We explain trends in dowry levels in Bangladesh by drawing
attention to an institutional feature of marriage contracts
previously ignored in the literature: mehr or traditional
Islamic bride-price. We develop a model of marriage
contracts in which mehr serves as a barrier to husbands
exiting marriage and a component of dowry as an amount that
ex ante compensates the groom for the cost of mehr. We
investigate how mehr and dowry respond to exogenous changes
in the costs of polygamy and divorce, and show that our
model gives a different set of predictions than traditional
models. We show that major changes in dowry levels took
place precisely after the legal changes, corresponding to
simultaneous changes in levels of mehr. © 2010 by the
President and Fellows of Harvard College and the
Massachusetts Institute of Technology.},
Doi = {10.1162/qjec.2010.125.3.1349},
Key = {fds237857}
}
@article{fds237854,
Author = {Ambrus, A and Azevedo, E and Kamada, Y},
Title = {Hierarchical cheap talk},
Journal = {Accepted by Theoretical Economics},
Volume = {8},
Number = {1},
Pages = {233-261},
Publisher = {The Econometric Society},
Year = {2011},
url = {http://public.econ.duke.edu/~aa231/hierarch_final04.pdf},
Abstract = {We investigate situations in which agents can communicate to
each other only through a chain of intermediators, for
example, because they have to obey institutionalized
communication protocols. We assume that all involved in the
communication are strategic and might want to influence the
action taken by the final receiver. The set of pure strategy
equilibrium outcomes is simple to characterize, is monotonic
in each intermediator's bias, and does not depend on the
order of intermediators; intermediation in these equilibria
cannot improve information transmission. However, none of
these conclusions holds for mixed equilibria. We provide a
partial characterization of mixed equilibria, and offer an
economically relevant sufficient condition for every
equilibrium to be outcome-equivalent to a pure equilibrium
and hence for the simple characterization and comparative
statics results to hold for the set of all equilibria. ©
2013 Attila Ambrus, Eduardo M. Azevedo, and Yuichiro
Kamada.},
Doi = {10.3982/TE1038},
Key = {fds237854}
}
@article{fds237856,
Author = {Ambrus, A and Pathak, P},
Title = {Cooperation over finite horizons: a theory and
experiments},
Journal = {Journal of Public Economics},
Volume = {95},
Number = {1-2},
Pages = {500-512},
Publisher = {Elsevier BV},
Year = {2011},
url = {http://public.econ.duke.edu/~aa231/public_good090510_ALL.pdf},
Abstract = {This paper shows that the presence of different types of
players - those who only care about their own material
payoffs and those who reciprocate others' contributions -
can explain the robust features of observed contribution
patterns in public good contribution games, even without the
presence of asymmetric information. We show what conditions
on reciprocity are sufficient for a unique perfect
equilibrium, in which contributions are decreasing. Under
these conditions, selfish players have enough future
benefits to induce subsequent contributions by reciprocal
players, and this incentive diminishes as the end of the
game approaches. The model explains the puzzling restart
effect and is consistent with various other empirical
findings. We also report the results of a series of
experiments, using a probabilistic continuation design in
which after each set of 10-period games, the group is
restarted with low probability. We find specific support for
the theory in our data, including that selfish players
(identified exogenously) stop contributing earlier than
reciprocal players, as directly implied by the model. ©
2010 Elsevier B.V.},
Doi = {10.1016/j.jpubeco.2010.11.016},
Key = {fds237856}
}
@article{fds325429,
Author = {Ambrus, A and Chaney, EJ and Salitskiy, I},
Title = {Appendix for Pirates of the Mediterranean: An Empirical
Investigation of Bargaining with Transaction
Costs},
Journal = {Economic Research Initiatives at Duke (ERID) Working
Paper},
Number = {116},
Year = {2011},
Month = {December},
Key = {fds325429}
}
@article{fds320220,
Author = {Ambrus, A and Egorov, G},
Title = {Commitment-Flexibility Trade-Off and Withdrawal
Penalties},
Journal = {Economic Research Initiatives at Duke (ERID)},
Number = {130},
Pages = {29 pages},
Year = {2012},
Month = {March},
Abstract = {Withdrawal penalties are common features of time deposit
contracts offered by commercial banks, as well as individual
retirement accounts and employer-sponsored plans. Moreover,
there is a significant amount of early withdrawals from
these accounts, despite the associated penalties, and
empirical evidence shows that liquidity shocks of depositors
are a major driving force of this. Using the
consumption-savings model proposed by Amador, Werning and
Angeletos in their 2006 Econometrica paper (henceforth AWA),
in which individuals face the trade-off between flexibility
and commitment, we show that withdrawal penalties can be
part of the optimal contract, despite involving
money-burning from an ex ante perspective. For the case of
two states (which we interpret as “normal times” and a
“negative liquidity shock”), we provide a full
characterization of the optimal contract, and show that
within the parameter region where the first best is
unattainable, the likelihood that withdrawal penalties are
part of the optimal contract is decreasing in the
probability of a negative liquidity shock, increasing in the
severity of the shock, and it is nonmonotonic in the
magnitude of present bias. We also show that contracts with
the same qualitative feature (withdrawal penalties for high
types) arise in continuous state spaces, too. Our
conclusions differ from AWA because the analysis in the
latter implicitly assumes that the optimal contract is
interior (the amount withdrawn from the savings account is
strictly positive in each period in every state). We show
that for any utility function consistent with their
framework there is an open set of parameter values for which
the optimal contract is a corner solution, inducing money
burning in some states.},
Key = {fds320220}
}
@article{fds320219,
Author = {Ambrus, A and Rozen, K},
Title = {Rationalizing Choice with Multi-Self Models},
Journal = {Economic Research Initiatives at Duke (ERID)},
Volume = {125},
Number = {128},
Pages = {42 pages},
Year = {2012},
Month = {May},
Abstract = {This paper studies a class of multi-self decision-making
models proposed in economics, psychology, and marketing. In
this class, choices arise from the set-dependent aggregation
of a collection of utility functions, where the aggregation
procedure satisfies some simple properties. We propose a
method for characterizing the extent of irrationality in a
choice behavior, and use this measure to provide a lower
bound on the set of choice behaviors that can be
rationalized with n utility functions. Under an additional
assumption (scale-invariance), we show that generically at
most five "reasons" are needed for every
"mistake."},
Key = {fds320219}
}
@article{fds320218,
Author = {Ambrus, A and Sandor, L and You, H},
Title = {Testing an Informational Theory of Legislation: Evidence
from the U.S. House of Representatives: Supplementary
Appendix},
Journal = {Economic Research Initiatives at Duke (ERID)},
Number = {122},
Pages = {13 pages},
Year = {2012},
Month = {October},
Abstract = {Supplementary Appendix to Testing an Informational Theory of
Legislation: Evidence from the U.S. House of
Representatives.},
Key = {fds320218}
}
@article{fds237855,
Author = {Ambrus, A and Greiner, B},
Title = {Imperfect public monitoring with costly punishment: An
experimental study},
Journal = {American Economic Review},
Volume = {102},
Number = {7},
Pages = {3317-3332},
Publisher = {American Economic Association},
Year = {2012},
Month = {December},
ISSN = {0002-8282},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000312093000007&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {This paper experimentally investigates the effects of a
costly punishment option on cooperation and social welfare
in long, finitely repeated public good contribution games.
In a perfect monitoring environment, increasing the severity
of the potential punishment monotonically increases average
net payoffs. In a more realistic imperfect monitoring
environment, we find a U-shaped relationship. Access to a
standard punishment technology in this setting significantly
decreases net payoffs, even in the long run. Access to a
severe punishment technology leads to roughly the same
payoffs as with no punishment option, as the benefits of
increased cooperation offset the social costs of punishing.
Copyright © 2012 by the American Economic
Association.},
Doi = {10.1257/aer.102.7.3317},
Key = {fds237855}
}
@article{fds237852,
Author = {Ambrus, A and Azevedo, EM and Kamada, Y and Takagi,
Y},
Title = {Legislative Committees as Information Intermediaries},
Journal = {Journal of Economic Behavior and Organization},
Volume = {94},
Pages = {103-115},
Publisher = {Elsevier BV},
Year = {2013},
ISSN = {0167-2681},
Abstract = {This paper considers a model of legislative decision-making,
in which information must be collected from a strategic
lobbyist. The legislature appoints a committee to
communicate with the lobbyist and propose a bill, and
determines whether the proposal is processed under open or
closed rule. Consistent with empirical evidence, it can be
optimal for the legislature to appoint a biased committee
and, depending on the lobbyist's bias, both open and closed
rule are used in equilibrium. For small lobbyist bias, it is
optimal to choose closed rule and a committee whose
interests are perfectly aligned with the lobbyist's. For
intermediate lobbyist bias, closed rule remains optimal with
a committee whose preferences lie between those of the
legislature and those of the lobbyist. For large lobbyist
bias, open rule and a committee biased against the lobbyist
become optimal. © 2013 Elsevier B.V.},
Doi = {10.1016/j.jebo.2013.08.003},
Key = {fds237852}
}
@article{fds237851,
Author = {Ambrus, A and Egorov, G},
Title = {Comment on "Commitment vs. Flexibility"},
Journal = {Econometrica},
Volume = {81},
Number = {5},
Pages = {2113-2124},
Publisher = {The Econometric Society},
Year = {2013},
Month = {January},
ISSN = {0012-9682},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000325084100012&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {This comment corrects two results in the 2006 Econometrica
paper by Amador, Werning, and Angeletos (AWA), that features
a model in which individuals face a trade-off between
flexibility and commitment. First, in contrast to
Proposition 1 in AWA, we show that money-burning can be part
of the ex ante optimal contract when there are two states.
Second, in contrast to Proposition 2 in AWA, we show that
money-burning can be imposed at the top (in the highest
liquidity shock state), even when there is a continuum of
states. We provide corrected versions of the above results.
© 2013 The Econometric Society.},
Doi = {10.3982/ECTA10739},
Key = {fds237851}
}
@article{fds320216,
Author = {Ambrus, A and Ishii, Y and Burns, J},
Title = {Gradual Bidding in Ebay-Like Auctions},
Journal = {Economic Research Initiatives at Duke (ERID)},
Number = {129},
Pages = {59 pages},
Year = {2013},
Month = {September},
Abstract = {This paper shows that in online auctions like eBay, if
bidders can only place bids at random times, then many di
fferent equilibria arise besides truthful bidding, despite
the option to leave proxy bids. These equilibria can involve
gradual bidding, periods of inactivity, and waiting to start
bidding towards the end of the auction - bidding behaviors
common on eBay. Bidders in such equilibria implicitly
collude to keep the increase of the winning price slow over
the duration of the auction. In a common value environment,
we characterize a class of equilibria that include the one
in which bidding at any price is maximally delayed, and all
bids minimally increment the price. The seller's revenue can
be a small fraction of what could be obtained at a
sealed-bid second-price auction, and in the worst
equilibrium it is decreasing in the value of the object.
With many bidders, we show that this equilibrium has the
feature that bidders are passive until near the end of the
auction, and then they start bidding incrementally.},
Key = {fds320216}
}
@article{fds320215,
Author = {Ambrus, A and Greiner, B and Pathak, P},
Title = {How Individual Preferences Get Aggregated in Groups - An
Experimental Study},
Journal = {Economic Research Initiatives at Duke (ERID)},
Number = {158},
Pages = {37 pages},
Year = {2013},
Month = {September},
Abstract = {This paper experimentally investigates how individual
preferences, through unrestricted deliberation, get
aggregated into a group decision in two contexts:
reciprocating gifts, and choosing between lotteries. In both
contexts we find that median group members have a
significant impact on the group decision, but particular
other members also have some influence. Non-median members
closer to the median tend to have more influence than other
members. By investigating the same individual’s influence
in different groups, we find evidence for relative position
in the group having a direct effect on influence. We do not
find evidence that group choice exhibits a shift in a
particular direction that is independent of member
preferences and caused by the group decision context itself.
We also find that group deliberation not only involves
bargaining and compromise, but it also involves persuasion:
preferences tend to shift towards the choice of the
individual’s previous group, especially for those with
extreme individual preferences.},
Key = {fds320215}
}
@article{fds325428,
Author = {Ambrus, A and Mobius, M and Szeidl, A},
Title = {Consumption Risk-Sharing in Social Networks},
Journal = {American Economic Review},
Volume = {104},
Number = {1},
Year = {2014},
Month = {January},
Abstract = {We develop a model in which connections between individuals
serve as social collateral to enforce informal insurance
payments. We show that: (i) The degree of insurance is
governed by the expansiveness of the network, measured with
the per capita number of connections that groups have with
the rest of the community. "Two-dimensional" networks?like
real-world networks in Peruvian villages?are sufficiently
expansive to allow very good risk-sharing. (ii) In second-
best arrangements, insurance is local: agents fully share
shocks within, but imperfectly between endogenously emerging
risk-sharing groups. We also discuss how endogenous social
collateral affects our results.},
Key = {fds325428}
}
@article{fds237850,
Author = {Ambrus, A and Lu, SE},
Title = {Almost fully revealing cheap talk with imperfectly informed
senders},
Journal = {Games and Economic Behavior},
Volume = {88},
Pages = {174-189},
Publisher = {Elsevier BV},
Year = {2014},
Month = {November},
ISSN = {0899-8256},
Abstract = {We show that in multi-sender communication games where
senders imperfectly observe the state, if the state space is
large enough, then there can exist equilibria arbitrarily
close to full revelation of the state as the noise in the
senders' observations gets small. In the case of replacement
noise, where the senders observe the true state with high
probability, we show this under mild assumptions, for both
unbounded and large bounded state spaces. In the case of
continuous noise, where senders observe a signal distributed
continuously over a small interval around the true state, we
establish this for unbounded state spaces. The results imply
that when there are multiple experts from whom to solicit
information, if the state space is large, then even when the
state is observed imperfectly, there are communication
equilibria that are strictly better for the principal than
delegating the decision right to one of the
experts.},
Doi = {10.1016/j.geb.2014.09.001},
Key = {fds237850}
}
@article{fds325426,
Author = {Ambrus, A and En Lu and SE},
Title = {A continuous-time model of multilateral bargaining},
Journal = {American Economic Journal: Microeconomics},
Volume = {7},
Number = {1},
Pages = {208-249},
Publisher = {American Economic Association},
Year = {2015},
Month = {January},
Abstract = {We propose a finite-horizon continuous-time framework for
coalitional bargaining, in which players can make offers at
random discrete times. In our model: (i) expected payoffs in
Markov perfect equilibrium (MPE) are unique, generating
sharp predictions and facilitating comparative statics; and
(ii) MPE are the only subgame perfect Nash equilibria (SPNE)
that can be approximated by SPNE of nearby discrete-time
bargaining models. We investigate the limit MPE payoffs as
the time horizon goes to infinity and players get infinitely
patient. In convex games, we establish that the set of these
limit payoffs achievable by varying recognition rates is
exactly the core of the characteristic function.},
Doi = {10.1257/mic.20100029},
Key = {fds325426}
}
@article{fds320214,
Author = {Ambrus, A and Ásgeirsdóttir, T and Noor, J and Sandor,
L},
Title = {Compensated Discount Functions: An Experiment on the
Influence of Expected Income on Time Preferences},
Journal = {Economic Research Initiatives at Duke (ERID)},
Number = {168},
Pages = {43 pages},
Year = {2015},
Month = {March},
Key = {fds320214}
}
@article{fds320213,
Author = {Ambrus, A and Asgeirsdottir, TL and Noor, J and Sándor,
L},
Title = {Supplement to 'Compensated Discount Functions: An Experiment
on the Influence of Expected Income on Time
Preferences'},
Journal = {Economic Research Initiatives at Duke (ERID) Working
Paper},
Number = {169},
Year = {2015},
Month = {March},
Abstract = {This Supplementary Appendix contains the English
translations of the experimental questionnaire, survey
questions, and instructions that were used in our
experimental sessions on June 9th and 10th of 2010. For the
original Icelandic language documents, please contact the
authors. The paper 'Compensated Discount Functions - An
Experiment on Integrating Rewards with Expected Income' to
which this Supplement applies is available at the following
URL: <a href=http://ssrn.com/abstract=2446602>http://ssrn.com/abstract=2446602</a>},
Key = {fds320213}
}
@article{fds325425,
Author = {Ambrus, A and Chandrasekhar, AG and Elliott, M},
Title = {Social Investments, Informal Risk Sharing, and
Inequality},
Journal = {Economic Research Initiatives at Duke (ERID) Working
Paper},
Number = {179},
Year = {2015},
Month = {March},
Key = {fds325425}
}
@article{fds320211,
Author = {Ambrus, A and Ishii, Y},
Title = {On Asynchronicity of Moves and Coordination},
Journal = {Economic Research Initiatives at Duke (ERID)},
Number = {185},
Pages = {47 pages},
Year = {2015},
Month = {March},
Abstract = {This paper shows that asynchronicity of moves can lead to a
unique prediction in coordination games, in an
infinite-horizon setting, under certain conditions on
off-equilibrium payoffs. In two-player games we derive
necessary and sufficient conditions for play ultimately
being absorbed in the Pareto dominant Nash equilibrium of
the stage game, for every Markov perfect equilibrium. For
players patient enough, the condition is that the Pareto
dominant Nash equilibrium is also risk dominant, but for
lower levels of patience the condition departs from simple
risk-dominance. For general n-player symmetric games with
patient players, we show that a necessary and sufficient
condition for the Pareto dominant Nash equilibrium to be the
unique limit outcome in all symmetric Markov perfect
equilibrium is a particular generalization of risk-dominance
for more than two players. We provide extensions to the
unique selection results to all subgame perfect Nash
equilibria, and to coordination games in which different
players prefer different Nash equilibria of the stage
game.},
Key = {fds320211}
}
@article{fds320210,
Author = {Ambrus, A and Greiner, B},
Title = {Democratic Punishment in Public Good Games with Perfect and
Imperfect Observability},
Journal = {Economic Research Initiatives at Duke (ERID)},
Number = {183},
Pages = {27 pages},
Year = {2015},
Month = {August},
Abstract = {In the context of repeated public good contribution games,
we experimentally investigate the impact of democratic
punishment, when members of a group decide by majority
voting whether to inflict punishment on another member,
relative to individual peer-to-peer punishment. Democratic
punishment leads to more cooperation and higher average
payoffs, both under perfect and imperfect monitoring of
contributions, primarily by curbing anti-social punishment
and thereby establishing a closer connection between a
member’s contribution decision and whether subsequently
being punished by others. We also find that participating in
a democratic punishment procedure makes even
non-contributors’ punishment intentions more
pro-social.},
Key = {fds320210}
}
@article{fds320208,
Author = {Ambrus, A and Baranovskyi, V and Kolb, A},
Title = {A Delegation-Based Theory of Expertise},
Journal = {Economic Research Initiatives at Duke (ERID)},
Number = {193},
Pages = {45 pages},
Year = {2015},
Month = {September},
Abstract = {We investigate competition in a delegation framework, with a
coarsely informed principal. Two imperfectly informed and
biased experts simultaneously propose action choices. A
principal with a diffuse prior, and only being able to
ordinally compare the two proposals, has to choose one of
them. The selected expert might receive a bonus payment. We
show that having a second expert benefits the principal,
even if the two experts have the same biases and the bonus
of the winner is zero. In contrast with other models of
expertise, in our setting the principal prefers experts with
equal rather than opposite biases. Increasing the bonus
brings experts closer to truthful reporting, but this only
benefits the principal up to a threshold level, with further
increases in the bonus strictly decreasing her payoffs. A
methodological contribution of our paper is characterizing
restrictions on the set of strategies which allows a formal
generalization of ex ante expected payoffs to games with
diffuse prior.},
Key = {fds320208}
}
@article{fds320209,
Author = {Ambrus, A and Baranovskyi, V and Kolb, A},
Title = {Supplementary Appendix to 'A Delegation-Based Theory of
Expertise'},
Journal = {Economic Research Initiatives at Duke (ERID)},
Number = {194},
Pages = {16 pages},
Year = {2015},
Month = {September},
Abstract = {This supplement provides welfare results not contained in
the main text and a proof of Lemma A.1. For small bonuses, a
mixed equilibrium exists if and only if a downward
equilibrium exists; if so, it is unique. For large bonuses,
we find a unique candidate for mixed equilibrium and show
that mixed and upward equilibria cannot co-exist. Also, we
give an example for equal biases, where this candidate is
indeed a mixed equilibrium. However, when biases are
different enough and the bonus is high, a mixed equilibrium
does not exist. Though a general analytical comparison is
infeasible, we show that mixed equilibria are inferior to
upward equilibrium or simple delegation in various special
cases.},
Key = {fds320209}
}
@article{fds320207,
Author = {Ambrus, A and Greiner, B and Sastro, A},
Title = {The Case for Nil Votes: Voter Behavior Under Asymmetric
Information in Compulsory and Voluntary Voting
Systems},
Journal = {Economic Research Initiatives at Duke (ERID)},
Volume = {154},
Number = {199},
Pages = {66 pages},
Publisher = {Elsevier BV},
Year = {2015},
Month = {December},
Abstract = {We experimentally study the impact of adding an explicit nil
vote option to the ballot in both compulsory and voluntary
voting settings. We investigate this issue in an
informational voting setting, in which some voters are
uninformed and face the swing voter’s curse, implying that
they can only affect the expected election outcome
adversely. We generate predictions using a simple model of
strategic voting in which some voters receive a
psychological benefit (along the lines of Riker and
Ordeshook (1968)) from choosing an action that they consider
a legitimate participation in the election. We test our
model in a double-blind pen-and-paper laboratory experiment,
and find that the main comparative predictions of the model
hold in the data, particularly strongly for compulsory
voting. In particular, both under compulsory and voluntary
voting, introducing a nil vote option reduces the number of
uninformed voters casting a vote for a candidate, increasing
voters’ expected welfare. Additionally, it eradicates
strategic invalid votes under compulsory
voting.},
Doi = {10.1016/j.jpubeco.2017.08.006},
Key = {fds320207}
}
@article{fds320205,
Author = {Ambrus, A and Egorov, G},
Title = {Delegation and Nonmonetary Incentives},
Journal = {Economic Research Initiatives at Duke (ERID)},
Volume = {171},
Number = {200},
Pages = {49 pages},
Publisher = {Elsevier BV},
Year = {2015},
Month = {December},
Abstract = {In many contracting settings, actions costly to one party
but with no direct benefits to the other (money-burning) may
be part of the explicit or implicit contract. A leading
example is bureaucratic procedures in an employer-employee
relationship. We study a model of delegation with an
informed agent, where the principal may impose money-burning
on the agent as a function of the agent’s choice of
action, and show that money-burning may be part of the
optimal contract. This result holds even if
action-contingent monetary transfers are possible, as long
as transfers from the principal to the agent are bounded
from below (as in limited liability or minimal wage
requirements). In fact, the optimal contract can involve a
combination of both efficient monetary incentives and
inefficient nonmonetary incentives through money burning.
Our model delivers some results novel to the delegation
literature. First, money-burning is more likely if the
principal is more sensitive to the choice of action than the
agent. This is consistent with the perception that there is
more bureaucratization in large organizations. Second,
money-burning is more likely if the agent’s limited
liability constraint is tighter relative to his
participation constraint. This implies that a higher minimum
wage distorts employment contracts towards using socially
wasteful nonmonetary incentives, leading to a Pareto
inferior outcome as the agent is still held down to his
reservation value through increased money
burning.},
Doi = {10.1016/j.jet.2017.06.002},
Key = {fds320205}
}
@article{fds320206,
Author = {Ambrus, A and Egorov, G},
Title = {Supplementary Appendix to 'Delegation and Nonmonetary
Incentives'},
Journal = {Economic Research Initiatives at Duke (ERID)},
Number = {201},
Pages = {21 pages},
Year = {2015},
Month = {December},
Abstract = {Supplementary Appendix to "Delegation and Nonmonetary
Incentives."},
Key = {fds320206}
}
@article{fds318150,
Author = {Ambrus, A and Calvano, E and Reisinger, M},
Title = {Either or Both Competition: A 'Two-Sided' Theory of
Advertising with Overlapping Viewerships},
Journal = {American Economic Journal: Microeconomics},
Volume = {8},
Number = {3},
Pages = {189-222},
Publisher = {American Economic Association},
Year = {2016},
Month = {August},
Abstract = {In media markets, consumers spread their attention to
several outlets, increasingly so as consumption migrates
online. The traditional framework for competition among
media outlets rules out this behavior by assumption. We
propose a new model that allows consumers to choose multiple
outlets and use it to study the effects on advertising
levels and the impact of entry and mergers. We identify
novel forces which reflect outlets' incentives to control
the composition of their customer base. We link consumer
preferences and advertising technologies to market outcomes.
The model can explain several empirical regularities that
are difficult to reconcile with existing
models.},
Doi = {10.1257/mic.20150019},
Key = {fds318150}
}
@article{fds325427,
Author = {Ambrus, A and Chaney, E and Salitskiy, I},
Title = {Pirates of the Mediterranean: An empirical investigation of
bargaining with asymmetric information},
Journal = {Quantitative Economics},
Volume = {9},
Number = {1},
Pages = {217-246},
Publisher = {The Econometric Society},
Year = {2018},
Month = {March},
Abstract = {We investigate the effect of delay on prices in bargaining
situations using a data set containing thousands of captives
ransomed from Barbary pirates between 1575 and 1692.
Plausibly exogenous variation in the delay in ransoming
provides evidence that negotiating delays decreased the size
of ransom payments, and that much of the effect stems from
the signalling value of strategic delay, in accordance with
theoretical predictions. We also structurally estimate a
version of the screening type bargaining model, adjusted to
our context, and find that the model fits both the observed
prices and acceptance probabilities well.},
Doi = {10.3982/QE655},
Key = {fds325427}
}
@article{fds343589,
Author = {Ambrus, A and Greiner, B and Zednik, A},
Title = {The Effects of a ‘None of the Above’ Ballot Paper Option
on Voting Behavior and Election Outcomes},
Journal = {Economic Research Initiatives at Duke (ERID) Working
Paper},
Number = {277},
Year = {2019},
Month = {March},
Key = {fds343589}
}
@article{fds346383,
Author = {Ambrus, A and Greiner, B},
Title = {Individual, Dictator, and Democratic punishment in public
good games with perfect and imperfect observability},
Journal = {Journal of Public Economics},
Volume = {178},
Year = {2019},
Month = {October},
Abstract = {In the context of repeated public good contribution games,
we experimentally compare the institution of democratic
punishment, where members of a group decide by majority
voting whether to inflict punishment on another member, with
individual peer-to-peer and dictatorial punishment
institutions. Democratic punishment leads to more
cooperation and higher average payoffs, both under perfect
and imperfect monitoring of contributions. A comparison with
dictatorial punishment suggests that the effect relative to
traditional peer-to-peer punishment primarily works by
curbing anti-social punishment and thereby establishing a
closer connection between a member's contribution decision
and whether subsequently being punished by
others.},
Doi = {10.1016/j.jpubeco.2019.104053},
Key = {fds346383}
}
@article{fds352348,
Author = {Ambrus, A and Field, E and Gonzalez, R},
Title = {Loss in the time of cholera: Long-run impact of a disease
epidemic on the urban landscape},
Journal = {American Economic Review},
Volume = {110},
Number = {2},
Pages = {475-525},
Year = {2020},
Month = {January},
Abstract = {How do geographically concentrated income shocks influence
the long-run spatial distribution of poverty within a city?
We examine the impact on housing prices of a cholera
epidemic in one neighborhood of nineteenth century London.
Ten years after the epidemic, housing prices are
significantly lower just inside the catchment area of the
water pump that transmitted the disease. Moreover,
differences in housing prices persist over the following 160
years. We make sense of these patterns by building a model
of a rental market with frictions in which poor tenants
exert a negative externality on their neighbors. This
showcases how a locally concentrated income shock can
persistently change the tenant composition of a
block.},
Doi = {10.1257/aer.20190759},
Key = {fds352348}
}
@article{fds357650,
Author = {Ambrus, A and Elliott, M},
Title = {Investments in social ties, risk sharing, and
inequality},
Journal = {The Review of Economic Studies},
Volume = {88},
Number = {4},
Pages = {1624-1664},
Publisher = {Oxford University Press},
Year = {2021},
Month = {July},
Abstract = {This article investigates stable and efficient networks in
the context of risk sharing, when it is costly to establish
and maintain relationships that facilitate risk sharing. We
find a novel trade-off between efficiency and equality: the
most stable efficient networks also generate the most
inequality. We then suppose that individuals can be split
into groups, assuming that incomes across groups are less
correlated than within a group but relationships across
groups are more costly to form. The tension between
efficiency and equality extends to these correlated income
structures. More-central agents have stronger incentives to
form across-group links, reaffirming the efficiency benefits
of having highly central agents. Our results are robust to
many extensions. In general, endogenously formed networks in
the risk-sharing context tend to exhibit highly asymmetric
structures, which can lead to stark inequalities in
consumption levels.},
Key = {fds357650}
}
@article{fds326998,
Author = {Ambrus, A and Kolb, A},
Title = {On defining ex ante payoffs in games with diffuse
prior},
Journal = {Economic Theory},
Volume = {72},
Number = {2},
Pages = {445-472},
Year = {2021},
Month = {September},
Abstract = {While the diffuse prior has been widely used in applied
economic theory for its technical convenience and as a way
of modeling complete lack of knowledge, it is not formally
defined, nor are ex ante payoffs in games under this prior.
In this paper, we provide a formal treatment of the diffuse
prior which can validate its application in games. We
consider stationary games, in which players’ signals are
translation invariant in the true state and players’
payoffs are translation invariant in actions together with
the state. We show that strategies which admit well-defined
expected payoffs under the diffuse prior are essentially
stationary, being almost translation invariant in signals.
Our analysis builds on two formal definitions. We define the
diffuse prior through a limit construction, using sequences
of well-defined priors that become increasingly dispersed. A
class of strategy profiles is admissible if for any strategy
profile, each player’s ex ante payoff along these
sequences converges to a limit that does not depend on the
particular sequence. A secondary contribution of the paper
is an extension of the concept of distributional strategies
(Milgrom and Weber in Math Oper Res 10:619–632, 1985) to a
class of multistage games.},
Doi = {10.1007/s00199-020-01292-y},
Key = {fds326998}
}
@article{fds359729,
Author = {Ambrus, A and Baranovskyi, V and Kolb, A},
Title = {A Delegation-Based Theory of Expertise},
Journal = {American Economic Journal: Microeconomics},
Volume = {13},
Number = {4},
Pages = {373-419},
Publisher = {American Economic Association},
Year = {2021},
Month = {November},
Abstract = {We investigate information aggregation and competition in a
delegation framework. An uninformed principal is unable to
perform a task herself and must choose between one of two
biased and imperfectly informed experts. In the focal
equilibrium, experts exaggerate their biases, anticipating
an ideological winner's curse. We show that having a second
expert can benefit the principal, even when equally or more
biased than the first expert. The principal can benefit from
commitment to an "element of surprise" and prefers experts
with equal rather than opposite biases.},
Key = {fds359729}
}
@article{fds371291,
Author = {Ambrus, A and Wayne, GAO and Milán, P},
Title = {Informal Risk Sharing with Local Information},
Journal = {Review of Economic Studies},
Volume = {89},
Number = {5},
Pages = {2329-2380},
Year = {2022},
Month = {October},
Abstract = {This article considers the effect of contracting limitations
in risk-sharing networks, arising for example from
observability, verifiability, complexity, or cultural
constraints. We derive necessary and sufficient conditions
for Pareto efficiency under these constraints in a general
setting, and we provide an explicit characterization of
Pareto efficient bilateral transfer profiles under CARA
utility and normally distributed endowments. Our model
predicts that network centrality is positively correlated
with consumption volatility, as more central agents become
quasi-insurance providers to more peripheral agents. The
proposed framework has important implications for the
empirical specification of risk-sharing tests, allowing for
local risk-sharing groups that overlap within the village
network.},
Doi = {10.1093/restud/rdab091},
Key = {fds371291}
}