Making a copy of an existing variable is highly useful e.g. when you want to experiment with a variable or to recode a variable without altering the original version.

Practical example

Dataset

StataData1.dta

Variable name	gpa
Variable label	Grade point average (Age 15, Year 1985)
Value labels	N/A

gen gpa2=gpa

As can be seen below, the new variable gpa2 will be an exact copy of the old variable gpa.

sum gpa gpa2

browse gpa gpa2