[Wake]

People seem to think MBTI includes motivations, which is incorrect, and the Keirsey Temperament Forums create a culture around this misinterpretation of the MBTI.

INTJ and INTP's all seem to think they're 5s, and the JCF Ni they talk about makes them feel brainy so it's not hard to type as the most intellectual Etype.

INFP, ISFP, INFJ tend to identify with the 4 description without being a 4 because it's so deep and emotional, but if they're truly that type or simply have similarities is the question.

ESTJ type 1, because they feel they need to be dominant and correct people, they must see the world in an idealistic way though it takes more than that to truly be a 1.

 

[Wake]

So what is more likely to be off, their MBTI type, or their ENNG ? or both ?

A mistyping takes place because people don't grasp what is necessary to be a Etype or have a MBTI preference. Given they are successful in their understanding of self I wouldn't say that either typology is better than the other in terms of mistyping. Maybe enneagram is mistyped more often because the tests are known to be inaccurate. The MBTI type is made up of four preferences though, any one of which can be misinterpreted. Both typologies have multiple definitions floating around and some are more accurate than others. Though I'm sure a more accurate typology exists, from my understanding it's hard to say either typology is better than the other in this way.

 

[Wake]

2s will probably mistype as Fe-users. (Yes, I'm also mixing MBTI and JCF right now. But I think that's legitimate since that's also part of why there are those confusions...)
6s can mistype as anything (BUT: depending on their actual CF and/or MBTI preferences)
5s will probably mistype as NTs
7s will probably mistype as EPs
8s will probably mistype as ETJs
1s will probably mistype as Js
9s will probably mistype as ..anything since they relate to anything...
3s will probably mistype as ETs (<= haha. ;P)
4s will probably mistype as INFs

Given that the subject types themselves starting with the preferences, why do you say that someone would mistype as those preferences? I would think that they would be characteristics most likely influenced by your Etype.

 

[Wake]

If a certain Enneagram type would automatically make you use certain cognitive functions that would mean that nobody could have an Enneagram type that's non-stereotypical for their MBTI type. But I have seen so many people (including myself) who aren't that stereotypical. @pinkrasputin, @Stephen and I have almost identical tritypes, yet our cognitive functions are completely different.

I also know of 1s with very different cognitive functions. Right now I can think of INFJ, ISTJ and INFP 1s I know. And I don't think that's limited to those. And the INFP 1 has mistyped himself as an INFJ, btw. But he's still an INFP.

I point to personal experience in dealing with the fixation of an Etype as making someone capable of typing outside of even the most likely MBTI function. Personally, I could never imagine type 1 being anything but J, and stats indicate a strong majority are, but there are some that aren't. We don't perceive our Etype's motivation quite the same way, and end up applying ourselves differently because our goal is different though generally of the same Etype.

 

[Wake]

J/P is not a very fixed thing... in Socionics an INFJ is and INFp and an INFP is an INFj. So where should you draw the line there? And actually I don't even believe it's possible to draw that line.

It is rather subjective, but to identify more with the typical P tendencies instead of J is hard to imagine.

I thought I would give my two cents on the topic, but MBTI isn't very appealing to me to carry on this conversation any further.