# How do decks work?

**URL:** <https://forum.surveyengine.com/t/how-do-decks-work/103>\
**Category:** Sampling & Quotas\
**Tags:** deck\
**Created:** [13 February 2023 18:37 UTC](https://forum.surveyengine.com/t/how-do-decks-work/103 "2023-02-13T18:37:16Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Freddo](https://dub1.discourse-cdn.com/flex017/user_avatar/forum.surveyengine.com/freddo/32/55_2.png) [@Freddo](https://forum.surveyengine.com/u/Freddo)\
**Post date:** [13 February 2023 18:37 UTC](https://forum.surveyengine.com/t/how-do-decks-work/103/1 "2023-02-13T18:37:16Z")

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For Q11 we need to randomize a vector of value with DECK? How does it work

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**Author:** ![benno](https://dub1.discourse-cdn.com/flex017/user_avatar/forum.surveyengine.com/benno/32/3_2.png) [@benno](https://forum.surveyengine.com/u/benno)\
**Post date:** [13 February 2023 21:17 UTC](https://forum.surveyengine.com/t/how-do-decks-work/103/2 "2023-02-13T21:17:30Z")

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Decks are a useful general purpose way of creating a ‘random-without-replacement’ draw from a pool of numbers from 1 to N where you specify the maximum number. This is applied at the segment level.

Random-without-replacement draws have advantages over purely random numbers.  
After N respondents - each number from 1 to N has been allocated exactly once. This means an even balance of random allocations in maintained across respondents.

In reality with respondent dropout and parallel allocation - perfect balance is not achievable, however SurveyEngine decks are continually re-balanced to recover unused allocations.

See the tutorials page for more information.  
[https://surveyengine.com/software/software-tutorials/](https://surveyengine.com/software/software-tutorials/)