# Why is the income wage variable incwage-capped? and how is the cap determined? 2016: 504,000, 2015:483,000... **URL:** \ **Category:** General\ **Created:** [November 21, 2017, 5:28pm UTC](https://forum.ipums.org/t/why-is-the-income-wage-variable-incwage-capped-and-how-is-the-cap-determined-2016-504-000-2015-483-000/2031 "2017-11-21T17:28:00Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![jglickman234](https://avatars.discourse-cdn.com/v4/letter/j/2bfe46/32.png) [@jglickman234](https://forum.ipums.org/u/jglickman234)\ **Post date:** [November 21, 2017, 5:28pm UTC](https://forum.ipums.org/t/why-is-the-income-wage-variable-incwage-capped-and-how-is-the-cap-determined-2016-504-000-2015-483-000/2031/1 "2017-11-21T17:28:00Z")
In the ACS survey, I noticed that the income wage variable- incwage- is capped. In 2016, it was capped at $504,000, at 2015 at $483,000. how was the capping level determined? why is there a cap at all? thanks for your help answering my questions. ---
**Author:** ![JeffBloem](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.ipums.org/jeffbloem/32/40_2.png) [@JeffBloem](https://forum.ipums.org/u/JeffBloem)\ **Post date:** [November 21, 2017, 6:32pm UTC](https://forum.ipums.org/t/why-is-the-income-wage-variable-incwage-capped-and-how-is-the-cap-determined-2016-504-000-2015-483-000/2031/2 "2017-11-21T18:32:00Z")
Income values are top-coded in order to preserve confidentiality within public use data. Above some threshold of income there are fewer and fewer individuals, and therefore without top-codes it could be possible to identify individuals in the public use data. In order to prevent this from happening the U.S Census Bureau implements a top-coding scheme. The specific top-code value depends on the specific sample of data you are using. These details can be seen on the [Codes Tab](https://usa.ipums.org/usa-action/variables/INCWAGE#codes_section). In particular, in ACS samples, the top-code represents the average income of those within the 99.5th percentile within each state.