[PDF] recoding categorical variables in stata

Does Stata handle categorical variables as factor variables?

Stata handles categorical variables as factor variables; see[U] 11.4.3 Factor variables. Categoricalvariables refer to the variables in your data that take on categorical values, variables such assex,group, andregion. Factor variables refer to Stata’s treatment of categorical variables.

What is a termindicator variable in Stata?

for variables that divide the data into more than two groups, and let’s use the termindicator variablefor categorical variables that divide the data into exactly two groups. Stata can convert continuous variables to categorical and indicator variables and categorical variablesto indicator variables.

What is a Recode statement?

The recode statement is only useful when grouping old categorical values into new categories, which is common in survey data analysis. We already saw how to go from an old categorical variable to a new categorical variable in the married example using the replace statement.

How do you recode a factor variable?

To be used as a factor variable, a categorical variable must take on nonnegative integer values. Ifyou have variables with negative values, recode them; see[D]recode. If you have string variables,you can useegen’sgroup()function to recode them, egen group(), labelandencodedo the same thing. We tend to useegen group(), label.See[D]egenand[D]encode.