Carl Jung and Isabel Briggs Myers' models of personality - Psychological Type and Myers Briggs - both contain Judging types and Perceiving types.  But, even though Isabel Briggs Myers based her type system on Jung's, her types contradict his.

This isn't just a case of Isabel Briggs Myers having twice as many types.  The same person could be categorised as a Perceiving Type in Isabel Briggs Myers' scheme and as a Judging Type in Carl Jung's scheme.

Which Types are Judging Types?

This diagram shows Isabel Briggs Myers' Judging types highlighted in yellow:

The next diagram shows Carl Jung's Judging types, also highlighted in yellow.

You can see that the two sets of highlighted, yellow types are different:

Both schemes contain types described in the Myers Briggs system as ENTJ, ESTJ, ESFJ and ENFJ.  In Jung's system, these four types correspond to two types called Extraverted Thinking Types and Extraverted Feeling Types (or Te and Fe, or Conductor and Coach in the MTR-i team role wheel).

However, Isabel Briggs Myers counts ISTJ, ISFJ, INTJ and INFJ as judging types, but in Jung's scheme the remaining judging types are Introverted Thinking (ISTP, INTP, or Scientist) and Introverted Feeling (ISFP, INFP, or Campaigner).

Different Definitions

The reason for this contradiction is that Isabel Briggs Myers and Carl Jung used different definitions, they defined Judging and Perceiving Types differently.

To determine whether a type is Judging or Perceiving, Carl Jung used the 'dominant' function (or mental muscle).  That is, if the 'most preferred' function is a Judging function, then that is a Judging type.

In Isabel Briggs Myers's definition, however, she didn't use the 'most preferred' function to determine the type, she used a more complicated definition.

To determine whether a type is Judging or Perceiving, Isabel Briggs Myers asked 'which function is being used to deal with the outer world of people and things?'  For introverts, the answer to that question is the 2nd favourite function, not the most preferred.  Hence, she arrives at a different categorisation to Carl Jung.

For example, in an ISTP, the most preferred function is Thinking, which is a judging function.  Hence someone with ISTP preferences would be described in Jung's scheme as a Judging type.

But Isabel Briggs Myers classifies ISTP as a Perceiving Type because the function ISTPs use to deal with the outer world is Sensing, which is a perceiving function.

Conclusion

Carl Jung and Isabel Briggs Myers agreed on what were Judging and Perceiving functions.  However, when it came to categorising them into Types they used different definitions, and so describe different sets of people.