# NGene design: ensure all alternatives to differ in at least one attribute

**URL:** <https://forum.surveyengine.com/t/ngene-design-ensure-all-alternatives-to-differ-in-at-least-one-attribute/210>\
**Category:** Experiments\
**Tags:** ngene\
**Created:** [21 November 2024 18:30 UTC](https://forum.surveyengine.com/t/ngene-design-ensure-all-alternatives-to-differ-in-at-least-one-attribute/210 "2024-11-21T18:30:12Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![yifeiwu](https://avatars.discourse-cdn.com/v4/letter/y/6de8d8/32.png) [@yifeiwu](https://forum.surveyengine.com/u/yifeiwu)\
**Post date:** [21 November 2024 18:30 UTC](https://forum.surveyengine.com/t/ngene-design-ensure-all-alternatives-to-differ-in-at-least-one-attribute/210/1 "2024-11-21T18:30:12Z")

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On the NGene Design page, is there a simple way to ensure that all alternatives in my design differ in at least one attribute? (i.e. no option is exactly the same?)

Or do I need to specify a series of restrictions using “logical constraint”? Thank you.

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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:** [12 August 2025 14:36 UTC](https://forum.surveyengine.com/t/ngene-design-ensure-all-alternatives-to-differ-in-at-least-one-attribute/210/2 "2025-08-12T14:36:25Z")

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Yi,  
We’re not Ngene experts but I would have thought this was automatic with D efficient designs - with unlablelled alternatives. So it’s likely this is a labelled experiment problem in which constraints should help here.

I can suggest coming up with an example where you can show this happening from an ngene script. Then post this on their forum - they are pretty active.

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