Progress Update #3

Hi Everyone!


In the final week of my research, I looked into the two remaining personality tests on my list: the Eysenck Personality Questionnaire and the NEO Personality Inventory. First, I wanted to find out about the development of the tests, and then I wanted to assess the reliability and validity of the two tests as measures of personality. First, the Eysenck Personality Questionnaire, which was originally created with 63 yes or no items designed to measure two domains of personality– extraversion and neuroticism, with a third scale built in called the Lie scale to assess the accuracy of a subject’s responses (namely, to ensure they did not select answers randomly). After its publication in 1963, the test was revised to include a third domain called psychoticism, and today the most recent version of the test contains 94 yes or no questions and measures the same three domains. One of the primary concerns that many psychologists have is the low reliability found by several studies in relation to the psychoticism scale. The authors of the test justify this lower level of consistency by pointing out that psychoticism measures several different facets of personality under a single umbrella, such as hostility, lack of empathy, nonconformism, etc. However, if anything this justification seems to indicate that the EPQ would be more reliable and better able to quantify personality if it assessed a greater number of domains so that each one could be more specific.


The NEO Personality Inventory in its most recent, revised form could be the solution to the central problem of the EPQ. Like the EPQ, the NEO-PI-R measures extraversion and neuroticism as personality domains, but instead of psychoticism the NEO-PI-R assesses agreeableness, conscientiousness, and openness to experience. It draws these domains from the Five-Factor Model (FFM) of personality psychology, a school of thought favored by most modern psychologists. The NEO-PI-R is also longer than the EPQ, with 240 items and 3 validity items, and responses are charted on a five point scale instead of a yes/no binary. In terms of its reliability and validity, the NEO-PI-R is largely supported by psychologists. Because it measures each of its five domains as continuous variables, it eliminates the inaccuracy inherent in results from the MBTI and similar personality assessments, and a five-point response scale allows for further nuance in the results of the test. Out of the four tests I studied, the NEO-PI-R checked the most boxes in terms of what psychologists look for when determining the psychometric soundness of a personality measure.


Overall, the four personality tests I read about in my research taught me a lot about personality psychology, the many uses of personality assessments in clinical, social, and business spheres and beyond, and about the slippery question of psychometric value when discussing any kind of psychological measure.


–Virginia Wyatt


  1. arcopeland says:

    Hi Virginia! This is such a cool topic to study for the summer! I’ll definitely be taking the one you recommended in this post 🙂 One of the most interesting things about personality tests to me, is that the questions are highly predictable in terms of what they intend the measure. Quiz takers can typically pick out which questions may show extraversion and neuroticism for instance, and will subconsciously adjust their responses based on this. I’m wondering if there is any way to correct this user error and provide more accurate results. As least for me, I get a different answer every time I take these quizzes! Would a longer, more in-depth assessment like NEO-PI-R fix this? Also, would simple yes/no questions or more complex 1-10 answering schemes work better in determining true personality? On one hand, yes/no questions are more clear for the quiz taker and would make quiz taking simpler, but a 1-10 scale allows quiz takers to respond with how they truly feel. However, introspection can be difficult. Anyways, thank you for these updates! I’ve enjoyed reading through them today, and I’m looking forward to your conclusion!