The special legal status of Indian tribes in the U.S. means that state excise taxes are not necessarily collected on cigarette purchases on Indian reservations. We focus on two under-studied but basic empirical economic questions this raises. Using novel data from New York surveys that asked...

Estimation of the covariance matrix of asset returns is crucial to portfolio construction. As suggested by economic theories, the correlation structure among assets differs between emerging markets and developed countries. It is therefore imperative to make rigorous statistical inference on...