Project Heartbeat! was a longitudinal study of metabolic and morphological changes in adolescents aged 8–18 years and was conducted in the 1990s. A study is currently being conducted to consider the relationship between a collection of phenotypes (including BMI, blood pressure, and blood...

Most standard missing-data techniques have been designed for cross-sectional data. A "forward-backward" multiple-imputation algorithm has been developed to impute missing values in longitudinal data (Nevalainen, Kenward, and Virtanen, 2009, Statistics in Medicine 28: 36577-3669) This technique...

Stata's graphics were completely rewritten for Stata 8, with further key additions in later versions. Its official commands have, as usual, been supplemented by a variety of user-written programs. The resulting variety presents even experienced users with a system that undeniably is large, often...

Fractional polynomial models are a simple yet very useful extension of ordinary polynomials. They greatly increase the available range of nonlinear functions and are often used in regression modeling, both in univariate format (using Stata's fracpoly command) and in multivariable modeling (using...

Cure models can be used to simultaneously estimate the proportion of cancer patients who are eventually cured of their disease and the survival of those who remain "uncured". One limitation of parametric cure models is that the functional form of the survival of the "uncured" has to be...

Mata is Stata's matrix programming language. StataCorp provides detailed documentation on it, but so far has failed to give users-and especially users who add new features to Stata-any guidance in when and how to use the language. This talk provides what has been missing. In practical ways, this...

Although survey data are sometimes weighted by their selection weights, it is often preferable to use auxiliary information available on the whole population to improve estimation. Calibration weighting (Deville and Sarndal, 1992, Journal of the American Statistical Association 87: 376-382) is...

In this presentation, I update Nichols and Schaffer's 2007 UK Stata Users Group talk on clustered standard errors. Although cluster-robust standard errors are now recognized as essential in a panel-data context, official Stata only supports clusters that are nested within panels. This...