Essays in information elicitation and market design

This dissertation consists of three essays in microeconomic theory. The first two focus on how to elicit information about the state of the world from strategic agents, either to make a decision or for its own sake. The third studies a model of decentralized two-sided matching markets. In "Mechanisms for making accurate decisions in biased crowds," I study decision rules for finding the true answer to a binary question using the opinions of biased agents. Taking majority rule as a baseline, I study peer-prediction decision rules, which ask agents to predict the opinions of others in addition to providing their own. Incorporating first-order beliefs into the decision rule has the potential to recognize the correct answer even when the majority is wrong. However, I show the majority rule is essentially the only deterministic, neutral, anonymous, and interim dominance solvable mechanism. I then characterize all randomized peer-prediction mechanisms with these properties, using this result to show majority rule is the optimal mechanism in this class. Finally, I consider a simple, non-incentive-compatible decision rule based on the median prediction that implements majority rule when all agents are strategic and improves on majority rule when an unknown subpopulation is honest. In "Minimum truth serums with optional predictions," I introduce a class of mechanisms for eliciting private correlated signals from a group of expected score maximizers without external verification or knowledge about the agents' belief structure. Built on proper scoring rules, these minimum truth serums ask agents to report a signal and a prediction of the signals of others. If two agents with the same signal have the same expectations about the signals of others, the Bayesian incentive compatibility of these mechanisms follows with no further assumptions on the agents' belief structure. With a slight modification, the mechanism is still feasible and incentive compatible when the prediction portion of the report is optional. In "Uncoordinated two-sided matching markets," I study a decentralized proposal model in joint work with Juan Fung. The study of two-sided matching markets is now a major subfield of market design, focused primarily on the variants of the deferred acceptance algorithm. As a centralized mechanism, deferred acceptance is guaranteed to return a stable match. However, there is little definite work on whether uncoordinated agents find a stable matching on their own and the consequences if not. We show that small to moderately large uncoordinated markets reach a stable match within n^2 proposals from each agent when the proposal strategy isn't completely naive. We also show that stopping the proposal process early before stabilizing results in a more egalitarian and higher welfare match, particular when the two sides of the market are unbalanced. This suggests uncoordinated markets wouldn't benefit from centralization unless there is an obvious failing like market unraveling

Matching Dynamics with Constraints

We study uncoordinated matching markets with additional local constraints that capture, e.g., restricted information, visibility, or externalities in markets. Each agent is a node in a fixed matching network and strives to be matched to another agent. Each agent has a complete preference list over all other agents it can be matched with. However, depending on the constraints and the current state of the game, not all possible partners are available for matching at all times. For correlated preferences, we propose and study a general class of hedonic coalition formation games that we call coalition formation games with constraints. This class includes and extends many recently studied variants of stable matching, such as locally stable matching, socially stable matching, or friendship matching. Perhaps surprisingly, we show that all these variants are encompassed in a class of "consistent" instances that always allow a polynomial improvement sequence to a stable state. In addition, we show that for consistent instances there always exists a polynomial sequence to every reachable state. Our characterization is tight in the sense that we provide exponential lower bounds when each of the requirements for consistency is violated. We also analyze matching with uncorrelated preferences, where we obtain a larger variety of results. While socially stable matching always allows a polynomial sequence to a stable state, for other classes different additional assumptions are sufficient to guarantee the same results. For the problem of reaching a given stable state, we show NP-hardness in almost all considered classes of matching games.Comment: Conference Version in WINE 201

The lifeboat problem

We study an all-pay contest with multiple identical prizes ("lifeboat seats"). Prizes are partitioned into subsets of prizes ("lifeboats"). Players play a twostage game. First, each player chooses an element of the partition ("a lifeboat"). Then each player competes for a prize in the subset chosen ("a seat"). We characterize and compare the subgame perfect equilibria in which all players employ pure strategies or all players play identical mixed strategies in the first stage. We find that the partitioning of prizes allows for coordination failure among players when they play nondegenerate mixed strategies and this can shelter rents and reduce rent dissipation compared to some of the less efficient pure strategy equilibria

The lifeboat problem

We study an all-pay contest with multiple identical prizes (lifeboat seats). Prizes are partitioned into subsets of prizes (lifeboats). Players play a two-stage game. First, each player chooses an element of the partition (a lifeboat). Then each player competes for a prize in the subset chosen (a seat). We characterize and compare the subgame perfect equilibria in which all players employ pure strategies or all players play identical mixed strategies in the first stage. We find that the partitioning of prizes allows for coordination failure among players when they play nondegenerate mixed strategies and this can shelter rents and reduce rent dissipation compared to some of the less efficient pure strategy equilibria. --All-pay contest,multiple prizes,rent dissipation,lifeboat

Matching under Preferences

Matching theory studies how agents and/or objects from different sets can be matched with each other while taking agents\u2019 preferences into account. The theory originated in 1962 with a celebrated paper by David Gale and Lloyd Shapley (1962), in which they proposed the Stable Marriage Algorithm as a solution to the problem of two-sided matching. Since then, this theory has been successfully applied to many real-world problems such as matching students to universities, doctors to hospitals, kidney transplant patients to donors, and tenants to houses. This chapter will focus on algorithmic as well as strategic issues of matching theory. Many large-scale centralized allocation processes can be modelled by matching problems where agents have preferences over one another. For example, in China, over 10 million students apply for admission to higher education annually through a centralized process. The inputs to the matching scheme include the students\u2019 preferences over universities, and vice versa, and the capacities of each university. The task is to construct a matching that is in some sense optimal with respect to these inputs. Economists have long understood the problems with decentralized matching markets, which can suffer from such undesirable properties as unravelling, congestion and exploding offers (see Roth and Xing, 1994, for details). For centralized markets, constructing allocations by hand for large problem instances is clearly infeasible. Thus centralized mechanisms are required for automating the allocation process. Given the large number of agents typically involved, the computational efficiency of a mechanism's underlying algorithm is of paramount importance. Thus we seek polynomial-time algorithms for the underlying matching problems. Equally important are considerations of strategy: an agent (or a coalition of agents) may manipulate their input to the matching scheme (e.g., by misrepresenting their true preferences or underreporting their capacity) in order to try to improve their outcome. A desirable property of a mechanism is strategyproofness, which ensures that it is in the best interests of an agent to behave truthfully

Decentralized Market Processes to Stable Job Matchings with Competitive Salaries

We analyze a decentralized trading process in a basic labor market where heterogeneous firms and workers meet directly and randomly, and negotiate salaries with each other over time. Firms and workers may not have a complete picture of the entire market and can thus behave myopically in the process. Our main result establishes that, starting from an arbitrary initial market state, there exists a finite sequence of successive myopic (firm-worker) pair improvements, or bilateral trades, leading to a stable matching between firms and workers with a scheme of competitive salary offers. An important implication of this result is that a general random process where every possible bilateral trade is chosen with a positive probability converges with probability one to a competitive equilibrium of the market.Decentralized market, job matching, random path, competitive salary, stability

Venture Cycles: Theory and Evidence

We demonstrate how endogenous information acquisition in venture capital markets creates investment cycles when competing financiers undertake their screening decisions in an uncoordinated way, thereby highlighting the role of intertemporal screening externalities induced by competition among venture capitalists as a structural source of instability. We show that uncoordinated screening behavior of competing financiers is an independent source of fluctuations inducing venture investment cycles. We also empirically document the existence of cyclical features in a number of industries such as biotechnology, electronics, financial services, healthcare, medical services and consumer products.screening, venture capital, investment cycles

Two Narratives of Platform Capitalism

Mainstream economists tend to pride themselves on the discipline\u27s resem­blance to science. But growing concerns about the reproducibility of economic research are undermining that source of legitimacy. These concerns have fueled renewed interest in another aspect of economic thought: its narrative nature. When presenting or framing their work, neoliberal economists tend to tell sto­ries about supply and demand, unintended consequences, and transaction costs in order to justify certain policy positions. These stories often make sense, and warn policymakers against simplistic solutionism