We have previously demonstrated Stata implementation of bivariate ramdom effects meta-analysis of the sensitivity and specificity of a single binary diagnostic test by means of the midas module (Dwamena NASUG2007; Dwamena WCSUG 2007). In this presentation we extend our work to paired-comparison...

This presentation will demonstrate how to perform diagnostic meta-analysis using user-written macros midas and xtmidas for Stata versions 9 and 10 respectively. Both midas and xtmidas are comprehensive programs of statistical and graphical routines for undertaking meta-analysis of diagnostic...

Methods for meta-analysis of diagnostic test accuracy studies must, in addition to unobserved heterogeneity, account for covariate heterogeneity, threshold effects, methodological quality and small study bias, whic constitute the major threats to the validity of meta-analytic results. These have...

The creation and testing of interaction terms in regression models can be very cumbersome, even in Stata 8. We propose a simple wrapping command, -fitint-, that fits any generalised linear model and tests any twoway interactions, as well as all main effects. There is no need to use -xi- because...

Among various structures in Stata for cycling through lists (whether lists of variable names, numbers, or arbitrary strings) are foreach and forvalues, introduced in Stata 7 in 2001, and for, introduced in Stata 3.1 in 1992, and revised in 5.0 (1997) and 6.0 (1999). Typically, each member of the...

Stata's matrix language, Mata, highlighted in Bill Gould's Mata Matters columns in the Stata Journal, is very useful and powerful in its interactive mode. Stata users who write do-files or ado-files should gain an understanding of the Stata-Mata interface: how Mata may be called upon to do one...

The “fallacies of the wrong level” (e.g., ecological fallacy) are a concern in much of social-science research. When appropriate data are available, researchers frequently use intra-class correlations or ANOVAs to decide whether to use individual-level data or whether to aggregate and...

The Gini coefficient is widely used to measure inequality in the distribution of income, consumption, and other welfare proxies. Decomposing this measure can help you understand the determinants of inequality. In this presentation, I will use income data from Mexico to illustrate a user-written...

Survey data comes often as a plain table containing cryptic variable names, numbers, and letters. To make sense of the data, the researcher is given a questionnaire or a code book that contains a list of variable names, their description, and an interpretation of the values (either a number or a...

In this presentation, I will investigate the determinants of property tax collection in Mexico. The tax is paid by all owners of land and dwellings in Mexico for the right of holding their properties, and is collected and managed by municipal authorities at the local level. This type of tax has...