Knowledge that Transforms

A seller with commitment power sets prices over time. Risk-averse buyers arrive to the market and decide when to purchase. We show that it is optimal for the seller to choose a constant high price punctuated by occasional episodes of sequential discounts that occur at random times. This optimal price-path has the property that the price a buyer ends up paying is independent of his arrival and purchase times, and only depends on his valuation. Our theory accommodates empirical findings on the timing of discounts.

We quantify micro and macro effects of changes in the potential benefit duration (PBD) in unemployment insurance. In Poland, the PBD is 12 months for the newly unemployed if the previous year’s county unemployment rate is more than 150% of the national average, and 6 months otherwise. We exploit this cut-off using regression discontinuity estimates on registry data containing the universe of unemployed from 2005 to 2019. For those whose PBD is directly affected by the policy rule, benefit recipients younger than 50, a PBD increase from 6 to 12 months leads to 13% higher unemployment. A decomposition analysis reveals that 12 months after an increase in the PBD, only half of the increase in unemployment is due to the effect on search effort (the micro effect) while the other half is due to increased inflows into unemployment. The total effect on unemployment, which includes equilibrium effects, is entirely explained by the increase in unemployment of workers directly affected by the policy change. We find no evidence of spill-overs on two distinct groups of unemployed whose PBD is unchanged and no effect on measures of labour market tightness.

This article provides a unified framework for studying the identification of counterfactual parameters in a general class of discrete outcome models, allowing for endogenous regressors and multidimensional latent variables, all without parametric distributional assumptions. Our main theoretical result is that, when the covariates are discrete, the infinite-dimensional latent variable distribution can be replaced with a finite-dimensional version that is equivalent from an identification perspective. The finite-dimensional latent variable distribution is constructed in practice by enumerating regions of the latent variable space with a new and efficient cell enumeration algorithm for hyperplane arrangements. We then show that bounds on a certain class of counterfactual parameters can be computed by solving a sequence of linear programming problems, and show how the researcher can introduce additional assumptions as constraints in the linear programmes. Finally, we apply the method to a mobile phone choice example with heterogeneous choice sets, and to an airline entry game example.

When selling goods like wireless spectrum or electricity contracts, designers often opt for core-selecting mechanisms—i.e. those that induce outcomes in the core—in order to balance revenue and efficiency goals. But increasingly, auctions—such as the Federal Communications Commission’s Incentive Auction and those explored for natural resources—seek to reallocate goods, not just sell them. We show that when bidders can both buy and sell, substitutability among goods is no longer sufficient or necessary for core selection. In particular, in these environments, core selection can fail even with a single good and positive revenue, and can succeed even when some or all bidders view goods as complements. Instead, we show that the key feature that determines core selection is heterogeneity among the bidders. With too much heterogeneity, reallocation mostly realises pre-existing gains from trade among the bidders, and core selection fails. With limited heterogeneity, most gains from trade among the bidders are created by the quantity auctioned, and a core-selecting mechanism is possible.

When inferring causal effects from correlational data, a common practice by professional researchers but also lay people is to control for potential confounders. Inappropriate controls produce erroneous causal inferences. I model decision-makers (DMs) who use endogenous observational data to learn actions’ causal effect on payoff-relevant outcomes. Different DM types use different controls. Their resulting choices affect the very correlations they learn from, thus calling for an equilibrium analysis of the steady-state welfare cost of bad controls. I obtain tight upper bounds on this cost. Equilibrium forces drastically reduce it when types’ sets of controls contain one another.

We revisit the recent revealed preference analysis of sophisticated quasi-hyperbolic consumers by Blow et al. [(2021), “Non-parametric Analysis of Time-Inconsistent Preferences”, The Review of Economic Studies, 88, 2687–2734] (BBC). We show that BBC’s revealed preference test is too lax. There are non-rationalizable data that would pass their test. A basic problem with their test is that it requires finding a certain endogenous elasticity, without regard to the rationalizing utility. Their approach motivates a more stringent test, also based on first-order conditions, that would connect the endogenous elasticity and utility: We show that this test is also too lax. Aside from testing, we also discuss the possibility of recovering model parameters. We show that, even when discount factors are exactly identified, the approach followed in BBC allows for incorrect parameter values to lie in their identified set.

I study repeated games with anonymous random matching where players can add or remove signals from their records. The ability to manipulate records introduces monotonicity constraints on players’ continuation values, under which sufficiently long-lived players will almost never cooperate. When players’ expected lifespans are intermediate, their ability to sustain cooperation depends on (i) whether their actions are complements or substitutes and (ii) whether manipulation takes the form of adding or removing signals.

It is well-known that individual beliefs cannot be identified using traditional choice data, unless we exogenously assume state-independent utilities. In this paper, I propose a novel methodology that solves this long-standing identification problem in a simple way. This method relies on extending the state space by introducing a proxy, for which the agent has no stakes conditional on the original state space. The latter allows us to identify the agent’s conditional beliefs about the proxy given each state realization, which in turn suffices for indirectly identifying her beliefs about the original state space. This approach is analogous to the one of instrumental variables in econometrics. Similarly to instrumental variables, the appeal of this method comes from the flexibility in selecting a proxy.

We develop a general model of discrete choice that incorporates peer effects in preferences and consideration sets. We characterize the equilibrium behaviour and establish conditions under which all parts of the model can be recovered from a sequence of choices. We allow peers to affect preferences, consideration, or both. We show that these peer-effect mechanisms have different behavioural implications in the data. This allows us to recover the set and the type of connections between the agents in the network. We then use this information to recover each agent’s preferences and consideration mechanisms. These nonparametric identification results allow for general forms of heterogeneity across agents and do not rely on the variation of either exogenous covariates or the set of available options (menus). We apply our results to model expansion decisions by tea chains and find evidence of limited consideration. We simulate counterfactual predictions and show how limited consideration slows market penetration and competition.

This paper develops a new framework for understanding when and how migrants shape culture, applying it to the Confederate diaspora—a small migrant group that left a large cultural imprint. Southern Whites that migrated after the Civil War played a pivotal role in spreading Confederate symbols and racial norms across the U.S. by the early 20th century. Their far-reaching influence stemmed from two key conditions: (i) an ideological intensity rooted in their experiences of slavery, secession, and military defeat and (ii) access to malleable power structures during westward expansion and post-war reconciliation. These conditions enabled them to transmit Confederate culture to both kin and non-Southern neighbours and to expand their reach by mobilising civil society organisation and leveraging positions of authority. They shaped policies and institutions that helped entrench racial norms and inequalities in labour markets, housing, and the criminal justice system. Our findings provide empirical foundations for understanding how migrants can transform local culture, rather than merely assimilate.