# Difference between performance specification and descriptive specification

**URL:** <https://community.blackspectacles.com/t/difference-between-performance-specification-and-descriptive-specification/4172>\
**Category:** Project Development & Documentation\
**Created:** [April 3, 2022, 3:28am UTC](https://community.blackspectacles.com/t/difference-between-performance-specification-and-descriptive-specification/4172 "2022-04-03T03:28:22Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![nmao](https://blackspectacles.com/uploads/images/16.png) [@nmao](https://community.blackspectacles.com/u/nmao)\
**Post date:** [April 3, 2022, 3:28am UTC](https://community.blackspectacles.com/t/difference-between-performance-specification-and-descriptive-specification/4172/1 "2022-04-03T03:28:22Z")

</div>

I am confused about performance specification and descriptive specification. In Ballast review manual, it says descriptive specification is a type of performance (open) specification. But there have been multiple questions in the practice exams that test on this two types of specifications. what are the difference between them? Thank you

---

<div class="post-metadata">

**Author:** ![Gfeldman](https://blackspectacles.com/uploads/images/5.png) [@Gfeldman](https://community.blackspectacles.com/u/Gfeldman)\
**Post date:** [April 5, 2022, 2:27am UTC](https://community.blackspectacles.com/t/difference-between-performance-specification-and-descriptive-specification/4172/2 "2022-04-05T02:27:12Z")

</div>

A descriptive spec is more of a map or written detail on products and properties and Performance specifications provide the results to be achieved, not the means of achieving the desired result. In lieu of codes or other ordinances, one may use a performance specification as a means of success.  
Hopefully, this helped!