To evaluate a Yes/No column in Dataverse, you need to specify the Yes and No values by selecting the appropriate options from the "Choice Set." This is typically in the format of '[Name of Yes/No Column] ([Name of Table])].[Selected Choice]'. Here's an example:

If(ThisItem.Active = 'Active (Dog Breeds and Characteristics)'.Yes, "Active", Blank())
For you it will be something like:
If(ThisItem.In_Spec = 'In_Spec (yourtablename)'.Yes,
RGBA(0,255,0,.5),
RGBA(255,0,0,.5))
Hint: The intellisense in the formula bar should help you fill in and validate the choice set by starting to type your column name.

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Rick Hurt