Return back to the issue, June 30, 2017
I want to bring your attention once again to this tag question about categorical data encoding. It has not been resolved satisfactory so far, to me.
1) I claim that we do need one special tag for (various types) of categorical data encoding/representation in analyses (types are: dummy or one-hot coding, deviation or effect coding, Helmert, repeated, etc. etc.). One omnibus tag for them. Just imagine it: we have endemic tag
[many-categories] but we don't have a tag for ubiquitous theme of how to represent categorical variables in this or that analysis or situation. We have currently only tag
[categorical-data] which covers it but is much more broad and general.
So, I recommend to create the tag. Wording candidates:
[categ-coding-scheme] or suggest your variant.
2) Dummy (aka one-hot) binary variables are the most well-known type of the categorical encoding / contrast variables. As currently, the tag
[dummy-variables] is a slave synonym to
[categorical-data]. Please recover it back as the tag on its own. Next thing: we yet keep currently separate tag
[indicator-variables] however. This is strange because it is conceptually the same thing as dummy variables (just less known term).
So, either map
[indicator-variables] to the restored
[dummy-variables] as its junior synonym; or, if you prefer
[indicator-variables], keep it, but then map
[dummy-variables] to it (not to
Original post Mar 6, 2017:
Please, consider these opportunities. Agree, disagree, your suggestions...
Moderators, please remove
[dummy-variables] tag from being a synonym to
[categorical-data]. These are definitely not synonyms. Categorical data can be represented as dummy variables, sure. That doesn't make the two concepts same at all.
[dummy-variables] should be kept a separate tag, and
[indicator-variables] be made its junior synonym. In a recent question/comment I've expressed my tendency to see indicators as a synonym of dummy. "Dummy", in turn, is just the binary type of "contrast variables", not any contrast variables.
[contrast-variables] should be created. It is elementary variables to which categorical data (factors) are recoded, explicitly or implicitly, in ANOVA-like procedures. Contrast variables correspond, but not synonymic, to
[contrasts] (comparing combinations of coefficients, we do have this tag already). Contrast variables include types "dummy", "deviation / effect", "Helmert", and so on.
If people agree and moderators recover
[dummy-variables] I could then proceed and fix the tagging of questions according to the above thesaurus.
So far I can see these three alternatives:
[dummy-set]) as binary indicator variables obtained out of a categorical variable. & create
[contrast-set]) as more general - not necessarily binary - such variables (I vote for this variant)
[indicator-set]) to be what "dummy variables" was defined just above. & define
[dummy-set]) to be what "contrast variables" was defined just above.
Both variants require
[dummy-variables] to be restored as a proper tag.
- Third solution: don't restore/define anyhow old
[dummy-variables]tag, however create tag
[contrast-variables]which, if you like, we may give another name, say