In a Markov decision problem with hidden state variables, a posterior distribution serves as a state variable and Bayes' law under an approximating model gives its law of motion. A decision maker expresses fear that his model is misspecified by surrounding it with a set of alternatives that are...

This paper describes a class of dynamic stochastic linear quadratic equilibrium models. A model is specified by naming lists of matrices that determine preferences, technology, and the information structure. Aggregate equilibrium allocations and prices are computed by solving a social planning...

A planner and agent in a permanent-income economy cannot observe part of the state, regard their model as an approximation, and value decision rules that are robust across a set of models. They use robust decision theory to choose allocations. Equilibrium prices reflect the preference for...

A decision maker is averse to not knowing a prior over a set of restricted structured models (ambiguity) and suspects that each structured model is misspecified. The decision maker evaluates intertemporal plans under all of the structured models and, to recognize possible misspecifications,...

A decision maker constructs a convex set of nonnegative martingales to use as likelihood ratios that represent alternatives that are statistically close to a decision maker's baseline model. The set is twisted to include some specific models of interest. Max-min expected utility over that set...

This paper describes a class of dynamic stochastic linear quadratic equilibrium models. A model is specified by naming lists of matrices that determine preferences, technology, and the information structure. Aggregate equilibrium allocations and prices are computed by solving a social planning...

A decision maker suspects that parameters of a set of structured parametric probability models vary over time in unknown ways that he does not describe probabilistically. He expresses a fear that all of these parametric models are misspeci ed by also wanting to consider alternative unstructured...

The authors adapt modern control theoretic techniques based on robust control theory to economic modelling and decision making. The main motivation behind the proposed approach is that concern about model misspecification in economics leads to decision strategies that work over the set of nearby...