# Reference Tag vs Expression Tag

**URL:** <https://forum.inductiveautomation.com/t/reference-tag-vs-expression-tag/84217>\
**Category:** Ignition\
**Tags:** ignition81\
**Created:** [January 12, 2024, 6:32pm UTC](https://forum.inductiveautomation.com/t/reference-tag-vs-expression-tag/84217 "2024-01-12T18:32:01Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![amarks](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/amarks/32/45610_2.png) [@amarks](https://forum.inductiveautomation.com/u/amarks)\
**Post date:** [January 12, 2024, 6:32pm UTC](https://forum.inductiveautomation.com/t/reference-tag-vs-expression-tag/84217/1 "2024-01-12T18:32:01Z")

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Using expression tags it is possible to directly reference only one tag, effectively making it a reference tag.

Is there any sort of performance implication using an expression tag like this? I would think it's _very_ small, if at all.

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<div class="post-metadata">

**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [January 12, 2024, 6:57pm UTC](https://forum.inductiveautomation.com/t/reference-tag-vs-expression-tag/84217/2 "2024-01-12T18:57:01Z")

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If you set it to event driven mode, it should be quite efficient. Do note that an expression tag is fundamentally one-way, where a reference tag is bidirectional.