Comparisons of within and between estimators using the conventional Hausman test may be subject to statistical problems if the within variation is not sufficiently large. Adopting an alternative asymptotic approximation, we propose a modification of Hausman test that is valid whether the within...

We show how to recursively calculate analytic first and second derivatives of the likelihood for a popular discrete-choice, dynamic programming model. These allow for decreased computing time, and are useful for de-bugging complicated program code and accurately estimating standard errors.