# CAN I ADD A VARIABLE TO AN ALREADY DOWNLOADED DATA SET FOR STATA?

**URL:** <https://forum.ipums.org/t/can-i-add-a-variable-to-an-already-downloaded-data-set-for-stata/511>\
**Category:** USA\
**Created:** [April 29, 2014, 4:08am UTC](https://forum.ipums.org/t/can-i-add-a-variable-to-an-already-downloaded-data-set-for-stata/511 "2014-04-29T04:08:00Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![jmedeiros](https://avatars.discourse-cdn.com/v4/letter/j/65b543/32.png) [@jmedeiros](https://forum.ipums.org/u/jmedeiros)\
**Post date:** [April 29, 2014, 4:08am UTC](https://forum.ipums.org/t/can-i-add-a-variable-to-an-already-downloaded-data-set-for-stata/511/1 "2014-04-29T04:08:00Z")

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I ALREADY DOWNLOADED A CENSUS IPUMS DATA IN STATA. I HAVE STARTED CLEANING THE DATA. CAN I ADD A VARIABLE TO AN ALREADY DOWNLOADED DATA SET?

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**Author:** ![grover](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.ipums.org/grover/32/5_2.png) [@grover](https://forum.ipums.org/u/grover)\
**Post date:** [April 29, 2014, 4:12pm UTC](https://forum.ipums.org/t/can-i-add-a-variable-to-an-already-downloaded-data-set-for-stata/511/2 "2014-04-29T16:12:00Z")

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It is possible to attach new variables to an already downloaded dataset using the variables [YEAR](https://usa.ipums.org/usa-action/variables/YEAR#description_section), [DATANUM](https://usa.ipums.org/usa-action/variables/DATANUM#description_section), [SERIAL](https://usa.ipums.org/usa-action/variables/SERIAL#description_section), and [PERNUM](https://usa.ipums.org/usa-action/variables/PERNUM#description_section) to [uniquely identify](https://usa.ipums.org/usa-action/faq#ques21) each record (all of these variables are automatically selected for each extract). Simply create a new extract with the variables you would like to attach to your previous extract, and then merge the two files using [YEAR](https://usa.ipums.org/usa-action/variables/YEAR#description_section), [DATANUM](https://usa.ipums.org/usa-action/variables/DATANUM#description_section), [SERIAL](https://usa.ipums.org/usa-action/variables/SERIAL#description_section), and [PERNUM](https://usa.ipums.org/usa-action/variables/PERNUM#description_section).

I hope this helps.