LOTS is an acronym, suggested by Cattell in 1957 and later elaborated by Block, to provide a broad classification of data source for personality psychology assessment.^[1]: 673 Each data source has its advantage and disadvantage. Research on personality commonly employ different data source so as to represent better the pattern of one's distinctive features.^[2][3]

• L-data, refer to the life-outcome data, such as age, education, income,^[4]: 481 student grades at school, criminal and conviction record^[5]: 13
• O-data, refer to observational data, such as observer rating from friends and family
• T-data, refer to standardised and objective test measurement, such as scored test, physiological response, reaction times (RT), implicit association test (IAT)
• S-data, refer to self-reports, such as questionnaires, personality test, structured interview^[4]: 481