Data on three proportions, probabilities, or fractions that add to 1 can be projected from a simplex to the plane and represented in a two-dimensional plot, commonly known as trilinear, triaxial, triangular, etc. The Stata program triplot has been available for some years as one way to produce...

This presentation focuses on predicted probabilities for multilevel models for dichotomous or ordinal responses. In a three-level model, for instance, with patients nested in doctors nested in hospitals, predictions for patients could be for new or existing doctors and, in the latter case, for...

Google has recently developed a new tool to allow users to create Google-like charts and maps: the Google Application Programming Interface (API) chart. This tool allows the user to create custom PNG pictures by sending an appropriate syntax code over the web. Here we present two Stata programs...

In regression and multivariate analysis, the presence of outliers in the dataset can strongly distort classical estimations and lead to unreliable results. To deal with this, several robust-to-outliers methods have been proposed in the statistical literature. In Stata, some of these methods are...

PanelWhiz is a collection of Stata Add-On scripts to make using panel datasets easier. It is designed for empirically minded economists, sociologists, political scientists, and demographers and allows the user to select vectors of variables at once. Matching and merging is done automatically. It...

The design decisions made by Stata in handling missing data in relational and logical expressions have, for the user, complex, pernicious, and poorly understood consequences. This presentation intends to substantiate that claim and to present two possible resolutions to the problem. As is well...

The parmest package creates output datasets (or results sets) with one observation for each of a set of estimated parameters, and data on the parameter estimates, standard errors, degrees of freedom, t or z statistics, p-values, confidence limits, and other parameter attributes specified by the...

The display of data or of results often entails the preparation of a variety of table-like graphs showing both text labels and numeric values. I will present basic techniques, tips, and tricks using both official Stata and various user-written commands. The main message is that whenever graph...

In recent years, more Stata programs have become available for nonparametric regression. The commands mrunning and mlowess make it possible to perform nonparametric regression over several dimensions. These techniques, however, impose the separable additivity of the effect of different...

Considerable headway has been made over the last 20 or 30 years into the isolation of points of failure in human energy metabolism using metabolic models of challenge data. These models are almost always differential in form, second-order (or higher), nonlinear, and involve both estimated and...