High frequency financial data allows us to learn more about volatility, volatility of volatility and jumps.  One of the key techniques developed in the literature in recent years has been bipower variation and its multipower extension, which estimates time-varying volatility robustly to...

This paper introduces a new class of multivariate volatility models which is easy to estimate using covariance targeting, even with rich dynamics. We call them rotated ARCH (RARCH) models. The basic structure is to rotate the returns and then to fit them using a BEKK-type parameterization of the...

 This paper assesses the quantitative impact of ambiguity on the historically observed financial asset returns and prices. The single agent, in a dynamic exchange economy, treats the conditional uncertainty about the consumption and dividends next period as ambiguous. We calibrate the agent's...

Unpredictability arises from intrinsic stochastic variation, unexpected instances of outliers, and unanticipated extrinsic shifts of distributions.  We analyze their properties, relationships, and different effects on the three arenas in the title, which suggests considering three associated...

We develop forecast-error taxonomies when there are unmodeled variables, forecast 'off-line'.  We establish three surprising results.  Even when an open system is correctly specified in-sample with zero intercepts, despite known future values of strongly exogenous variables, changes in...

This paper develops a model in which supply of a non-renewable resource can adjust through two margins: the rate of depletion and the rate of field opening.  Faster depletion of existing fields means that less of the resource can ultimately be extracted, and optimal depletion of open fields...

We investigate what it means for one act to be more ambiguous than another. The question is evidently analogous to asking what makes one prospect riskier than another, but beliefs are neither objective nor representable by a unique probability. Our starting point is an abstract class of...

Whether they are financial, economic, or psychological, discount rates affect most economic decisions: investment and savings, hirings and firings, defaults and refinancing, financial and economic reforms, learning and experimentation, and any other decision with long-term consequences, such as...

In models with a representative infinitely lived household, modern versions of tax smoothing imply that the steady-state of government debt should follow a random walk.  This is unlikely to be the case in OLG economies, where the equilibrium interest rate may differ from the policy-maker's rate...

This paper is largely motivated by the empirical observation that GP visits per person under the NHS have increased in England since the mid-1970s, while list sizes have decreased over the same period  A hypothesis consistent with this observation is that larger list sizes are associated with...