Based on my real life observations, the one true subtype system is contact/inert (this also coincidentally works better with mathematical modelling than any other subtype system).

Contact/inert system summary

In contact/inert subtypes, all subtypes are basically identical for rational/irrational and extravert/introvert but are shifted towards abstract/involved (aristocratic quadras) or implicit/explicit (democratic quadras). Having a null subtype (and just leaving the functions at their basic levels) also appears to be a thing that happens in real life.

An overview of a few things that I think are evidence for this system:

- Tons of ESIs are intro drama, musical theatre, opera, etc. With a strong inert subtype, they essentially have a beta NF subtype. I've seen ILE opera singers (which is definitely the stereotype of how ILEs are), and ILE incidentally also basically has an EIE subtype.
- A lot of NFs are scientists, inventors, computer programmers, etc. If they have an NT subtype, this makes sense.
- "Creative" subtypes rarely get mistaken for their mirrors from anything I've seen. More often, it seems they get mistaken for their supervisee, dual, semi-dual superego, or beneficiary. Now, what functions do these types in general have in common? (Hint: 3/5 have the same ego/id functions as each other, and 5/5 don't even have the lead in their ego or id.) "Dominant" subtypes seem to tend to get mistaken their supervisor, benefactor, mirror, activator, or even conflictor. Again, look at what these types have in common.
- You also have lots of "creative" subtypes who introverted or extraverted types who score as highly introverted or extraverted on Big 5 personality tests when the standard systems should suggest they be ambiverted that way (which is not social ambiversion), and likewise with rational and irrational "creative" subtypes who score very high or low on conscientiousness when standard systems suggest that they should be more in the middle due to being "rational" and "irrational" subtypes with the creative "switching places" with the lead. In contact/inert, rather than emphasizing introverted or extraverted or rational or irrational functions in general, you merely accentuate different introvert/extravert and rational/irrational functions that are still in line with the main type, and this allows a proper explanation for these results.


I dislike other subtype systems because I get contradictory results trying to use them. I've gotten both dominant and creative as well as no subtype in the standard subtype system based on different descriptions, dominant in DCNH, no discernable subtype in accepting/producing... all of this stuff seems quite contradictory to me. But using contact/inert doesn't seem to have contradictions like that.


Also, from a highly theoretical, mathematical perspective for all of you who are into that, if you locate all the functions on a 4-dimensional structure (the easiest is a 4-cube, but that's possibly not the most accurate based on diagrams I've seen) and rotate it and project it, for each of the types, the functions given in the contact/inert system incidentally seem to be the ones that get emphasized or deemphasized together depending on how you line them up to begin with. Maybe I just haven't looked hard enough, but that doesn't seem to happen for any other subtype system no matter how you line up the functions, so already this one is more consistent just from a perspective. That plus stuff like the real life evidence I put seems to point to this as definitely being the correct system.


Also, if anyone has a list of Reinin dichotomy self-ratings or other-people-ratings with definitely/maybe/don't know ratings, I'd like to line those up with types and subtypes to see if subtypes can be confirmed that way. We would find, say, a "Ti"-ILE and see if their maybe/don't know dichotomies line up more with the differences between ILE and LII or between ILE and LSE (which seems more similar to ILE from a purely function-based perspective).