In Stata, how do I estimate the confidence interval (CI) for a proportion?

In Stata, the confidence interval (CI) for a proportion can be estimated using the proportion command (.PROPORTION). Entering .PROPORTION varlist can produce estimates of proportions, standard errors, and CIs for the categories identified by the values in each variable of varlist.

For example, consider a data set consisting of two variables: gender, with two categories, male and female; and smoke, with three categories, non-smoking, light-smoking, and heavy-smoking. To estimate the proportion of each smoking group and the corresponding CI, the command is:

To include missing values as a category of smoke, the command is:

To estimate the proportions and CIs over groups of gender, the command is:

For more on the proportion command, refer to the Stata Reference, or use the help command (.HELP PROPORTION) in Stata.

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