Standard identification tag is indentify-this-xxx so I suggest we keep identify-this-instrument so it is probably not necessary to keep both.
Should we burn instrument-identification?
Having enough points for identify-this-instrument, I could (only) suggest a merge with instrument-identification. People should vote for this merge now.
But I'm not sure which one will be the master though. I mean, it should be identify-this-instrument, but I don't know how to actually do it.
There are currently:
I think these stats indicate that both tags are almost equally popular. Since we have a large number of identification tags in the standard format [tag:identify-this-*], it makes sense to keep identify-this-instrument as the main tag and mark instrument-identification as its synonym.
I think it is helpful to mark synonyms in this case rather than burning the tags because a new user who wants to ask a question related to instrument identification could naturally type identification into the tagging box and this keyword should helpfully lead to identify-this-instrument. In fact, I think it's reasonable to have such synonyms for every identification tag, just to be sure.
In my opinion, instrument-identification should be dropped in favor of identify-this-instrument and the tags for existing questions switched over.
Even if we don't drop instrument-identification, we should still switch over the tags to match the standard form.
