Personality Questionnaire Validity and Reliability Synopsis

December, 1998

Overall: We estimate that the Personality Questionnaire will indicate an English-speaking adult’s personality type accurately 85% of the time in a non-controlled (i.e. over the internet) environment. Resulting types are repeatable 75% of the time in a non-controlled environment, and 95% of the time in a controlled environment. Unless otherwise noted, these statistics were generated from a set of 100,000 subjects.

1^st Validation Technique: Best Approach Method. This method incorporates “Content” and “Criterion-related” validity assessment. Best Approach was used during the development of the Personality Questionnaire to ensure that we were starting with a good basic indicator. We were assured of content validity by ensuring that the creator of the Personality Questionnaire was an expert on psychological type, and on determining which behaviors were attributed to which personality functions and attitudes.

2^nd Validation Technique: Comparison Method. This method was used during first-phase and second-phase testing and validation of the Personality Questionnaire. It was used primarily to validate the end-results of the Personality Questionnaire. We compared Personality Questionnaire results against the results of other well-known instruments, namely the MBTI® and Keirsey’s Temperament Sorter. Our goal was to produce the same type as these comparable indicators at least 75% of the time in an uncontrolled environment. We “released” the questionnaire once we achieved this goal. Another revision after release brought us up to 85% matching.

3^rd Validation Technique: Averages Method. We used this method to validate the individual questions that make up the Personality Questionnaire. This was used periodically throughout the implementation and revision of the questionnaire.

For this method, we checked that answers to specific questions fell within ten percentage points of expected norms. Expected norms of the general population are as follows: 60% Extraverted, 40% Introverted, 75% Sensing, 25% Intuitive, 50% Thinking, 50% Feeling, 50% Judging, 50% Perceiving. Using 5000 questionnaire results, we checked that each question rendered results within 10% points of these expected norms. If the question did not meet these standards, it was revised and re-tested until it did.

Reliability Technique: All reliability data was determined via Repetition.

Elements that will affect validity and reliability of the Personality Questionnaire:

Mastery of English. PQ reliability goes down for subjects whose native language is not English.

Age. PQ is most valid for ages 20-30, and least valid for those under 16 and those over 60. Results can be reliably repeated for all ages, except for under 16.
State of mind. Individuals who are under extreme stress, or under treatment for a mental condition may not be typed accurately.