# In Stata, how do I create a new variable based on existing data?

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 natural log of `v1`

and create a new variable (e.g., `v1_log`

), use:

gen v1_log = log(v1)

For additional help, see the help files within Stata (for each of the following topics, enter the corresponding `help`

command):

Topic | Command |
---|---|

Using functions | `help functions` |

Using `gen` |
`help gen` |

Using `egen` |
`help egen` |

If you have questions about using statistical and mathematical software at Indiana University, contact Research Analytics. Research Analytics is located on the IU Bloomington campus at Woodburn Hall 200; staff are available for consultation Monday-Friday 9am-noon and by appointment.

*This is document* afrg *in the Knowledge Base.*

*Last modified on* 2016-11-15 08:34:27*.*