Someone who was interested in measuring a person's source traits, as described by raymond cattell, would use the neo personality inventory california psychological inventory (cpi) sixteen personality factors questionnaire (16pf) minnesota multiphasic personality inventory (mmpi)

Raymond Catell's work sprouted from Gordon Allport. Allport proposed that there are 4,500 traits there is to humans. Catell worked on by narrowing down this numbers. He reached to as low as 171 traits. But he reasoned out that some traits are synonymous. For example, being caring, warm and nice are synonymous traits. Instead, he grouped like traits into 16 personalities. These are the following: abstractedness, warmth, apprehension, emotional stability, liveliness, openness to change, perfectionism, privateness, intelligence, rule consciousness, tension, sensitivity, social boldness, self-reliance, vigilance and dominance

Through the sixteen personality factors questionnaire (16pf), you are asked about your responses and preferences on situational scenarios. You answer through a scale from high to low. You can answer strongly agree, agree, neutral, disagree and strongly disagree. Your answers are calculated through factor analysis and you can know your personality type.