Sum up and create new variable with STATA
Following are examples of how to create new variables in Stata using the gen (short for generate) and egen commands: To create a new variable (e.g., newvar ) and set its value to 0 , use: gen newvar = 0 To create a new variable (e.g., total ) from the transformation of existing variables (e.g., the sum of v1 , v2 , v3 , and v4 ), use: gen total = v1 + v2 + v3 + v4 Alternatively, use egen with the built-in rowtotal option: egen total = rowtotal(v1 v2 v3 v4) Note: The egen command treats missing values as 0 . To create a variable (e.g., avg ) that stores the average of four variables (e.g., v1 , v2 , v3 , and v4 ), use: gen avg = (v1 + v2 + v3 + v4) / 4 Note: Use the / (slash) to denote division and an * (asterisk) for multiplication. Alternatively, use egen with the built-in rowmean option: egen avg = rowmean(v1 v2 v3 v4) Stata also lets you take advantage of built-in functions for variable transformations. For example, to take the natura...