Roodman (Stata Journal, 2011) introduced the program cmp for using maximum likelihood to fit multiequation combinations of Gaussian-based models such as tobit, probit, ordered probit, multinomial probit, interval censoring, and continuous linear. This presentation describes substantial...

Biographical data gathered in surveys is often stored in spell format, allowing for overlaps between spell states. This gives useful information to researchers but leaves them with a very complex data structure, which is not easy to handle. I present my work on the ado-package newspell. It...

When one estimates discrete choice models, the mixed logit approach is commonly superior to simple conditional logit setups. Mixed logit models not only allow the researcher to implement difficult random components but also overcome the restrictive IIA assumption. Despite these theoretical...

Econometricians have begun to devote more attention to spatial interactions when carrying out applied econometric studies. The new command we are presenting, xsmle, fits fixed- and random-effects spatial models for balanced panel data for a wide range of specifications: the spatial...

Biplots display correlations and differences in means and standard deviations of many variables on one graph, together with the values of the plotted variables and approximations of the Euclidean distance between the observations. Biplots are useful for identifying clusters of observations,...

The recent addition of support for the CMYK colour model to Stata 8 allows graphs from Stata to be used where colour separation is required for printing. This paper outlines work being done at the Office for National Statistics to use Stata for graphics in our flagship "Economic Trends"...

Systematic reviews of randomised trials are now widely recognised to be the best way to summarise the evidence on the effects of medical interventions. A systematic review may (though it need not) contain a meta-analysis, `a statistical analysis which combines the results of several independent...

Searches for genes using linkage analyses with genetic markers placed across the entire human genome are hypothesis-free experiments, which represent an extreme form of multiple testing. As such, the low p-values required to obtain nominal significance make accurate diagnostics essential to...

The Stata command xtreg estimates the random-effects linear regression model, for which the random effects are assumed to be normally distributed with zero mean and non-negative variance, s^2_{i,t}. Testing homogeneity across units is equivalent to testing the null hypothesis H_0: s^2_{i,t} = 0,...

Time-to-event endpoints are a common outcome of interest in randomised clinical trials. The primary analysis should usually be by intention-to-treat, giving an indication of the effectiveness of the intervention in a population as a whole. However, the benefit specifically for an individual...