He is currently centennial professor at the London School of Economics, James Meade Professor of Economics Emeritus at the University of Oxford, professorial fellow at Nuffield College Oxford, and research principal at the Office of Financial Research at the U.S. Department of the Treasury.
He has been centennial professor at the London School of Economics since 2015 and remains a professorial fellow of Nuffield College, Oxford.
These stability concepts are not appropriate for analyzing social and economic systems which are constantly perturbed by idiosyncratic behavior and mistakes, and individual and aggregate shocks to payoffs.
A state is stochastically stable if it attracts positive weight in the stationary distribution of the Markov chain.
In an influential book, Individual Strategy and Social Structure, Young provides a clear and compact exposition of the major results in the field of stochastic evolutionary game theory, which he pioneered.
This means that the Markov chain is ergodic, so there is a unique stationary distribution which characterizes the long-run behavior of the process.
By backing off from rationality in this way, Foster and Young show that there are natural and robust learning procedures that lead to Nash equilibrium in general normal form games.
At the same time, the presence of multiple equilibria implies that less closely connected individuals in the population could arrive at a very different norm.
Young has also made significant applied contributions to understanding the diffusion of new ideas, technologies and practices in a population.
In an influential 2009 paper, Young turned attention to the diffusion dynamics that can result from different adoption rules in a well-mixed population.
Young characterized the mean dynamic of each of these processes under general forms of heterogeneity in individual beliefs and preferences.
Young shows that the Shapley value is the only symmetric and efficient solution concept that is solely computed from a player's marginal contributions in a cooperative game.
This justifies the Shapley value as the measure of a player's productivity in a cooperative game and makes it particularly appealing for cost allocation models.
[3][4] The Kemeny–Young method is a voting system that uses preferential ballots and pairwise comparison counts to identify the most popular choices in an election.
Using a simple probabilistic model for these noisy signals, Young showed that the Kemeny–Young method was the maximum likelihood estimator of the true preference order.
Young further argues that Marquis de Condorcet himself was aware of the Kemeny-Young rule and its maximum-likelihood interpretation, but was unable to clearly express his ideas.