# Help with Expression Tag Path

**URL:** <https://forum.inductiveautomation.com/t/help-with-expression-tag-path/15950>\
**Category:** Ignition\
**Created:** [November 9, 2017, 7:14pm UTC](https://forum.inductiveautomation.com/t/help-with-expression-tag-path/15950 "2017-11-09T19:14:25Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![ryan97103](https://avatars.discourse-cdn.com/v4/letter/r/cab0a1/32.png) [@ryan97103](https://forum.inductiveautomation.com/u/ryan97103)\
**Post date:** [November 9, 2017, 7:14pm UTC](https://forum.inductiveautomation.com/t/help-with-expression-tag-path/15950/1 "2017-11-09T19:14:25Z")

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I’m trying to create an expression tag to calculate the median for a dataset, but I keep getting an error that there is an invalid tag path. I know it’s a problem with the syntax that I used. Below is the user manual entry for Median

median({Root Container.Table.data}, “Weight”)

So the dataset is located in the root container area which is in another folder under the Windows group in the Project browser. Below is what I have:

median({Windows\Project 1.Root Container.CycleTimes.data}, “Value”)

Any ideas or is there a good tutorial on specifying path in an expression tag?

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**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:** [November 9, 2017, 7:18pm UTC](https://forum.inductiveautomation.com/t/help-with-expression-tag-path/15950/2 "2017-11-09T19:18:05Z")

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A property binding can only reference other components in the same window. You’ll have to pass parameters when the other window is opened, or route the data through a client tag.