InterType uses the "Majors PTI" to test for PsycheType.
Dr Mark S. Majors is a counselling psychologist with extensive psychometric credentials. He is the author and developer of the MajorsPTI™, MajorsOEM™ and Majors PT-Elements™) and principal developer of the Interstrength X-Styles Assessment. He provided the data analysis on the 1994 Strong Interest Inventory and the MBTI Form M and Form Q, developed the IRT scoring for the MBTI Form Q, and co-authored the MBTI Form Q Manual. In addition to the test development, Mark trains pastoral counsellors with an emphasis on the use of personality assessment for conflict resolution through the acceptance of differences and personal growth. He has developed and presents leadership training seminars that train leaders to serve others by using personality and individual differences to facilitate optimum performance. He has provided 19 years of successful individual and couples/marital counselling and coaching using personality differences and has authored numerous books, manuals and articles on personality differences and biblical psychology. He received his Bachelor of Science and Master of Science degrees in psychology from Iowa State University and his PhD in counselling psychology from the University of Nebraska–Lincoln.