Cronbach's $\alpha$ is an estimate of the reliability of a psychometric test. It's admittedly rather field-specific, and I don't think many people outside of psychology or psychometrics have ever heard of it. Nevertheless, it and its properties seem to be squarely on topic as CV.
And we have no less than 149 questions on it. But no tag.
Skimming through the first couple of questions, it seems like few questions mention Cronbach's $\alpha$ but would not profit from the tag. (Little wonder, since it's a rather specific thing.) Thus, I propose that:
- We create a tag cronbachs-alpha.
- Some Higher Being (moderator? SE developer?) mass-retags-without-bumping all questions that contain "Cronbach's alpha", perhaps looking specifically at those questions that already have the five maximum tags.
I'll post a couple of possible actions. Please upvote whatever seems best to you.