Welcome to From the help desk. From the help desk is written by the people in Technical Services at StataCorp and deals with issues that they have found to be of concern to a large fraction of Stata users. It is the rare column in this series that deals with sophisticated programming issues...

This article demonstrates that, although there is no command in Stata for fitting hurdle models, the parameters of a hurdle model can be estimated in Stata rather easily using a combination of existing commands. We also include a likelihood evaluator to be used with Stata's ml facilities to...

Polynomial distributed lag models (PDLs) are finite-order distributed lag models with the impulse-response function constrained to lie on a polynomial of known degree. You can estimate the parameters of a PDL directly via constrained ordinary least squares, or you can derive a reduced form of...

In this presentation, I cover how to use Stata for survey data analysis assuming a fixed population. We will begin by reviewing the sampling methods used to collect survey data, and how they affect the estimation of totals, ratios, and regression coefficients. We will then cover the three...

Stata has a rich set of operators for specifying factor variables in linear and nonlinear regression models. I will show how to test for the effects of factor variables in these models. I will also show how to compare and contrast these effects using linear combinations of the model coefficients.

In this presentation, I cover how to use Stata for survey data analysis assuming a fixed population. We will begin by reviewing the sampling methods used to collect survey data, and how they affect the estimation of totals, ratios, and regression coefficients. We will then cover the three...