There may be times that you receive a file that has many (or all) of the variables defined as strings, that is, character variables.  The variables may contain numeric values,…
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Consider the following mixed model: use https://stats.idre.ucla.edu/stat/data/depression, clear mixed depression i.group visit || sid: visit, cov(un) stddev Performing EM optimization: Performing gradient-based optimization: Iteration 0: log likelihood = -826.15973 Iteration…
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I don’t know if there is a standard definition of doubly wide data, but we will use it to mean data collected by subject on multiple time points on multiple…
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There are two easy ways to create dummy variables in Stata. Let’s begin with a simple dataset that has three levels of the variable group: input group 1 1 2…
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How do we detect if our data set has duplicate observations in Stata? Let’s look at the following data set with some duplicate observations in it. list id female race…
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Data management with dyadic data can be difficult. Before analyzing dyadic data, one may wish to know how many unique dyads appear in a dataset and create an ID variable…
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When performing data analysis, it is very common for a given model (e.g. a regression model), to not use all cases in the dataset. This can occur for a number…
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Standard methods of performing factor analysis ( i.e., those based on a matrix of Pearson’s correlations) assume that the variables are continuous and follow a multivariate normal distribution. If the…
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EFA within a CFA framework, as the name implies, combines aspects of both EFA and CFA. It produces a factor solution that is close to an EFA solution while providing…
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Here is a small (3×3) Stata example of a matrix in which each element is exponentiated.  You can generalize this example to any kind of elementwise matrix operation. matrix x…
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