ARCHIVED: In Stata, how do I get aggregate statistics and save them into a data set?

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Stata's collapse command computes aggregate statistics such as mean, sum, and standard deviation and saves them into a data set. When you execute the command, an existing data set is replaced with the new one containing aggregate data.

Suppose you want to get the sum of a variable x1 and the mean of a variable x2 for males and females separately. Consider the following example:

  . collapse (sum) x1 (mean) x2, by(male)

Note that male is set to 1 for male and 0 for female. The new data set has two observations with three variables: male, x1, and x2.

If you want to save into different variable names, specify the names, for example:

  . collapse (sum) new_x1=x1 (mean) new_x2=x2, by(male)

If you have questions about using statistical and mathematical software at Indiana University, contact the UITS Research Applications and Deep Learning team.