Interests: Experiments, game theory, mechanism design, some individual choice stuff, some other stuff.

See my Google scholar profile.


Current Working Papers & Work In Progress
Healy, Paul J. and Greg Leo, "Minimal Experiments"
Submitted

Summary: You have a model you want to test. Or, you want to classify subjects into "types" in some model. What's the smallest experiment that can accomplish these goals? We have a graph-theoretic way of answering that qusetion.

Download:    20-Min. Presentation    

Healy, Paul J. and Renkun Yang, "The Walker-Groves-Ledyard Mechanism: Improving Individual Rationality Without Sacrificing Simplicity or Stability"
Submitted.

Summary: The title kind of says it all. Our new mechanism is a hybrid between Groves-Ledyard (1977) and Walker (1981). It's stable, unlike Walker. And it reduces IR violations compared to G-L, but only in expectation.


Healy, Paul J. and John Kagel, "Testing Elicitation Mechanisms via Team Chat"

Summary: Multiple price lists should be better than binarized scoring rules for eliciting beliefs, but in practice they're about the same. Good news: team chat reveals that people aren't trying to manipulate these mechanisms.

Download:    75-Min. Presentation    

Healy, Paul J., "Epistemic Experiments: Utilities, Beliefs, and Irrational Play"1

Summary: I elicit a ridiculous amount of stuff from people playing games. Classical centipede games and prisoners' dilemmas definitely have social preferences. They're Bayesian games! There's some irrationality out there, too. But it goes away when strategic uncertainty is removed.

Download:    90-Min Presentation    60-Min Presentation    20-Min. Presentation    

Healy, Paul J. and Samantha Stelnicki, "A Direct Test of Hedging in Ambiguity Experiments"

Summary: ``Hedging'' means you realize that the random choice of which question is paid can actually eliminate ambiguity, if you look at things the right way. We design an experiment to see if people realize this. Turns out they don't.


Healy, Paul J.; Matthew Lewis; and Ryan Oprea, "Edgeworth Cycles: An Experimental Test of Markov Perfection"1

Summary: Markov perfect equilibrium (MPE) requires that players react only to payoff-relevant information. In a repeated duopoly, Maskin & Tirole (1991) prove that Edgeworth cycles can be a MPE. We find cycles in the lab, but subjects also respond to recent information that's not payoff-relevant.

Download:    75-Min. Presentation    

Healy, Paul J.; Ritesh Jain; and Ryan Oprea, "Belief-Free Strategies in Repeated Games with Stochastically-Perfect Monitoring: An Experimental Test"

Summary: We study a repeated prisoners' dilemma with private monitoring, except the whole history gets revealed (privately) at random points in time. Subjects can revise their current-period action after seeing the true history, but shockingly they don't! That's consistent with belief-free play.

Download:    60-Min. Presentation    



Refereed Publications

Agranov, Marina, Paul J. Healy and Kirby Nielsen, "Stable Randomisation"
Economic Journal, 133: 2553–2579. October 2023.

Summary: You randomize here?/ You will randomize there, too./ It’s a stable trait.

Download:    20-Min. Presentation    Working Paper Version    Supplementary Materials

Healy, Paul J. and Hyoeun Park, "Model Selection Accuracy in Behavioral Game Theory: A Simulation"
European Economic Review, 152: 104362. February 2023.

Summary: People use either AIC/BIC or cross-validation to pick which behavioral model fits data best. But how often do they actually pick the "right" model? With cross validation it can fail pretty badly! AIC/BIC perform better, but are too infelxible.

Download:    Working Paper Version    40-Min. Presentation    

Azrieli, Yaron; Christopher P. Chambers; and Paul J. Healy, "Constrained Preference Elicitation"
Theoretical Economics, 16: 507–538. May 2021.

Summary: If you ask someone their favorite things from k menus, you're eliciting only partial information about their entire preference. However, it is incentive compatible if you just pay one randomly. What other kinds of partial information could you elicit? Depends, but pretty much that's it.


Azrieli, Yaron; Christopher P. Chambers; and Paul J. Healy, "Incentives in Experiments with Objective Lotteries."1
Experimental Economics, 23: 1–29. March 2020.

Summary: In our other paper on experiment incentives we model gambles as Savage acts, which are very general. Here we repeat the exercise when gambles are viewed as objective lotteries. In practice the conclusions are the same, but the characterization is more beautiful here.

Download:    Working Paper    

Chambers, Christopher P.; Paul J. Healy; and Nicolas Lambert, "Proper Scoring Rules with General Preferences: A Dual Characterization of Optimal Reports." Games & Economic Behavior, 117: 322–341. September 2019.

Summary: A risk averse agent will misreport their beliefs in a proper scoring rule. We use duality techniques to characterize what beliefs they will report. Useful if the indirect utility function is easier to work with. We also show how to bound the degree of misreport with CARA preferences.

Download:    Working Paper    

Dormady, Noah and Paul J. Healy, "The Consignment Mechanism in Carbon Markets: A Laboratory Investigation."1
Journal of Commodity Markets, 14: 51–65. June 2019.

Summary: In some markets where pollution permits are auctioned off, a few players get consigned an initial allocation of permits and receive the revenue from their sale. How does this alter the auction outcome? We test this setting in the lab.

Download:    Working Paper    

Azrieli, Yaron; Christopher P. Chambers; and Paul J. Healy, "Incentives in Experiments: A Theoretical Analysis."1
Journal of Political Economy, 126(4): 1472–1503. August 2018.

Summary: If we assume only monotonicity (dominated gambles are never chosen), paying for one random period (the RPS mechanism) is typically the only incentive compatible way to pay subjects. Paying every period is similarly justified if we assume a 'no complementarities at the top' (NCaT) condition. Which should you use? That's your decision.

Download:    Online Appendices    Full Working Paper Version    20-Min. Presentation    90-Min. Presentation    

Brown, Alexander and Paul J. Healy, "Separated Decisions."1 European Economic Review, 101: 20–34. January 2018.

Summary: In a multiple price list experiment (eg, Holt-Laury), we find that paying one randomly is not incentive compatible when all decisions are shown in a single table or list. When we show each decision on a separate screen, then it becomes incentive compatible. Yeah, subjects exhibit more multiple switches, but those are their true preferences!

Download:    Working Paper Version    20-Min. Presentation    

Healy, Paul J. and Ritesh Jain, "Generalized Groves-Ledyard Mechanisms."
Games & Economic Behavior, 101: 204–217. January 2017. (Special issue in honor of my advisor, John Ledyard.)

Summary: Nobody knows this, but Groves & Ledyard's (1977) mechanism is actually just a VCG mechanism where people with non-quadratic preferences announce quadratic approximations. We generalize this procedure to construct some really messy-looking mechanisms.

Download:    Working Paper Version      30-Min. Presentation

Georganas, Sotiris, Paul J. Healy, and Roberto Weber, "On the Persistence of Strategic Sophistication." Journal of Economic Theory, 159(A): 369–400. September 2015.

Summary: We test cross-game stability of the Level-k/CogHi model. Ann's estimated level in one set of games fails to predict her level in another. In fact, Ann being a higher level than Bob in the first set of games doesn't predict who's higher in the other.

Download:    Working Paper Version      Data     Instructions    

Healy, Paul J. and Michael Peress, "Preference Domains and the Monotonicity of Condorcet Extensions." Economics Letters, 130: 21–23. May 2015.

Summary: Let C be the set of preference profiles that admit a Condorcet winner. Any social choice correspondence that picks the Condorcet winner and whose domain is a subset of C can be implemented. But if you allow for more preferences, it cannot be implemented.

Download:    Working Paper Version

Cox, Caleb, Matthew Jones, Kevin Pflum, and Paul J. Healy, "Revealed Reputations in the Finitely-Repeated Prisoners' Dilemma." Economic Theory, 58(3): 441–484. April 2015.1

Summary: Ann and Bob play a finitely-repeated prisoners dilemma (FRPD). Ann can see how Bob played a previous FRPD against Charlie. If Bob was good to Charlie, then Ann trusts Bob more than she would've if she hadn't seen his history. But if Bob was a jerk to Charlie, Ann doesn't trust him less! Standard reputation models can't explain this.

Download:    Working Paper Version    20-Min. Presentation    

Georganas, Sotiris, Paul J. Healy, and Nan Li, "Frequency Bias in Consumers' Perceptions of Inflation:
An Experimental Study
." European Economic Review, 67: 144–158. April 2014.1

Summary: Our experiments suggest that, when perceiving inflation, people tend to overweight those goods whose prices they see frequently. For example, if you see gas prices shooting up, you think the entire economy is inflating faster than it really is.

Download:     Working Paper Version

Healy, Paul J. and Laurent Mathevet, "Designing Stable Mechanisms for Economic Environments."
Theoretical Economics, 7(3): 609–661. September 2012.1

Summary: We characterize all mechanisms that implement Walrasian or Lindahl allocations in Nash equilibrium. Then we prove that they can't be dynamically stable if their message space is one-dimensional, but can be stable if messages are two-dimensional. Example mechanisms are given.

Download:     Working Paper Version (with corrections since publication)     Presentation

Chambers, Christopher P. and Paul J. Healy, "Updating Toward the Signal."
Economic Theory, 50(3): 765–786. August 2012.

Summary: For normal distributions, the posterior mean always lies between the prior mean and the signal. That's not true in general. We characterize distributions for which that is true. Symmetry and unimodality of the error distribution are important.

Download:     Working Paper Version     Presentation

Chambers, Christopher P. and Paul J. Healy, "Reversals of Signal-Posterior Monotonicity for
Any Bounded Prior
." Mathematical Social Sciences, 61(3): 178–180. May 2011.

Summary: Fix any bounded prior. We can construct a signal distribution and two possible signals where the higher signal is actually worse news, in terms of stochastic dominance of the posterior. (A failure of MLRP says this must be true for some prior; we say here it can be true for any.)

Download:     Working Paper Version

Healy, Paul J., Sera Linardi, J. Richard Lowery, and John O. Ledyard,
"
Prediction Markets: Alternative Mechanisms for Complex Environments with Few Traders."
Management Science, 56(11): 1977–1996. November 2010.1

Summary: A prediction market works great if you have lots of traders to help equilibrate prices. When you don't, we find that incentivized, iterated polls perform better.

Download:     Working Paper Version     Presentation

Healy, Paul J., "Equilibrium Participation in Public Goods Allocations."
Review of Economic Design, 14(1–2): 27–50. March 2010.1 (Special issue in honor of Leo Hurwicz.)

Summary: Suppose you use an incentive compatible mechanism to determine an ideal public goods allocation. But then some people don't mail in their check to the social planner. If you can't punish them, then no allocation better than the endowment is achievable when the economy grows large.

Download:     Working Paper Version     Presentation     MATLAB script for drawing Kolm triangles

Moore, Don A. and Paul J. Healy, "The Trouble With Overconfidence."
Psychological Review, 115(2): 502–517. April 2008.

Summary: First, we distinguish between overplacement, overestimation, and overprecision. Then we show negative correlation between overplacement and overestimation as task difficulty varies, and rationalize this observation via a simple Bayesian argument.

Correction: On p.505 the correct formula is α = vE / (vS + vL + vE). Thanks to Evan Calford and Mark Dean for catching this.

Download:     Working Paper Version    

Healy, Paul J., "Group Reputations, Stereotypes, and Cooperation in a Repeated Labor Market."
American Economic Review, 97(5): 1751–1773. December 2007.

Summary: I show how rational cooperation between groups can be sustained when sufficient stereotyping (modeled as a belief in type correlation among group members) is present. Behavior in experimental labor markets ('gift exchange games') is consistent with this theory.

Download:     Working Paper Version     Appendix     Data     Instructions     Presentation

Healy, Paul J., John O. Ledyard, Charles Noussair, Harley Thronson, Peter Ulrich, and Julio Varsi,
"
Contracting Inside an Organization: An Experimental Study."
Experimental Economics, 10(2): 143–167. June 2007.

Summary: Using simple theory and lab experiments, we show that the current method of funding space science projects within NASA is inferior to a proposed alternative with a cost sharing feature. (Thronson, Ulrich & Varsi are/were NASA employees.)

Download:     Working Paper Version     Data     Instructions     Presentation

Healy, Paul J., "Learning Dynamics for Mechanism Design: An Experimental Comparison of
Public Goods Mechanisms
." Journal of Economic Theory, 129(1): 114–149. July 2006.

Summary: We know dynamic stability (supermodularity?) is important for public goods mechanisms. Here, I test 5 mechanisms, and provide a simple best-reply dynamic that predicts play (and convergence) reasonably well. (This was my job market paper.)

Download:     Working Paper Version     Data     Instructions     Presentation

Healy, Paul J. and Charles Noussair, "Bidding Behavior in the Price is Right Game: An Experimental Study." Journal of Economic Behavior & Organization, 54(2): 231–247. June 2004.

Summary: Non-equilibrium behavior in the 4-player `contestants row' game on the Price is Right is replicated in the lab. But when the game is made simpler (requiring less backwards induction), players play equilibrium more frequently.

Download:     Working Paper Version     Data     Instructions
View a non-technical summary of this paper.
I was interviewed by CBC Radio (Canada) in May, 2007 about this paper. You can listen to the broadcast.



Papers in Proceedings
Moore, Don A. and Paul J. Healy, "Bayesian Overconfidence."
Academy of Management 2007 Best Papers Proceedings

Summary: This is a 6-page version of "The Trouble With Overconfidence", Psychological Review 115(2): 502–517. April 2008.




Non-Refereed & Editor-Refereed Publications
Healy, Paul J., "Comment on 'Thirteen Reasons Why the Vickrey-Clarke-Groves Process is Not Practial'."
Operations Research 55 (March-April 2007) Online Forum Commentary

Summary: I agree with Rothkopf's shortcomings of the VCG mechanism, but urge computer scientists to look beyond dominant strategy implementation.




Older Unpublished Papers
Conley, John and Paul J. Healy, "Public Goods, Bounded Attention Spans and Equilibrium in the Internet Economy"

Summary: Take a standard G.E. model. As the economy grows large, the Pareto optimal public good level is infinitely larger than the private good levels. This seems unrealistic. We fix this by assuming attention constraints limit agents' consumption of public goods.


Conlon, John, Paul J. Healy, and Yeochang Yoon, "Information Cascades With Informative Ratings: An Experimental Test"

Summary: This was supposed to be a test of Yoon's (2015) prediction that truthful-but-noisy ratings can actually increase certain types of information cascades. But the crazy subjects just loved to purchase regardless of the history! Appears to be some sort of activity bias going on.


Healy, Paul J., "Belief Learning in an Unstable Infinite Game"

Summary: In belief-based learning models, agents form predictions based on past play and then best respond to them. To uncover the model players actually use, I either track their calculator usage or have them make incentivized predictions as they play.

Download:    Presentation

Healy, Paul J. and Brian W. Rogers, "Alternative Specifications of Multiplicative Risk Premia"

Summary: Pratt gave a risk premium for gambles in which a random variable gets added to your wealth. We give several notions of a risk premium for gambles in which your wealth gets multiplied by a random variable.


Healy, Paul J. and Don Moore, "Bayesian Overconfidence"

Summary: This is a working paper version of "The Trouble With Overconfidence", writen for an economics audience and with more focus on the theory. This paper won the 2007 Roman Weil prize at CMU's Tepper School of Business.

Download:    Appendix     Presentation     Data (.xls)

Healy, Paul J., "Betting Behavior in Two-Person Games with Different Starting Positions:
An Experiment Based on 'Final Jeopardy'
"

Summary: In 1999 I was an undergraduate student in Tim Cason's Experimental Economics (ECON 690) course at Purdue. I ran a pilot experiment testing behavior in Final Jeapordy against the predictions of Metrick (1995, AER).




Ph.D. Dissertation
Healy, Paul J., Institutions, Incentives, and Behavior: Essays in Public Economics and Mechanism Design
California Institute of Technology, 2005.



Survey Presentations
"Incentive Compatible Experiments"
Updated: Apr. 15, 2022

"Behavioral Mechanism Design"
University of Arizona on Oct. 15-16, 2008
Download:    Part 1    Part 2



Other Documents
Graduate Econometrics Review Book

Summary: I wrote this while studying for qualifier exams in graduate school. It's incomplete and messy. And I failed the exam.


healy.bib

Summary: This is a master record of all BibTeX entries I've entered over the years. Last updated: 4/27/17 10:50:08pm.




Financial Support Sources
  1. NSF Grant #SES-0847406: "CAREER: Behavioral Mechanism Design". 2009–14.
  2. NSF Grant #SES-1426967: "Eliciting the Type Space in Extensive-Form Game Forms". 2014–16.