The QA manager where I work just informed me there is a bug in my desktop app due to the sign-on prompt being "Operator Id" when it should be "Operator ID". Her argument being that "Id" refers to the ego portion of Freud's "psychic apparatus" and is not semantically correct.
Now being an anal engineer (AE) I of course had to go and lookup Id vs ID and from my cursory investigations (google) it seems ID is just as commonly used for Freud's ego as Id is.
So my reasoning would be that Id is a shortened version of "Identifier" and is more correct or at least more commonly used than ID which would typically indicate a two word abbreviation.
I could just change the UI but then I wouldn't be holding up my profession as an AE so I was wondering if there any best practices or references for this sort of thing that I could use to support my argument? Keeping in mind that this question relates to the user interface and not the source code where abbreviations and casing are a whole different branch of philosophy.
According to Merriam-Webster, the abbreviation is "ID". If it were a correct abbreviation, it would have to be "Id." with the period.