- Male college students, followed 3 years, Harvard University, USA, 1957-60
- N = 17
- Non Response:
- 37%: 9 dropouts, incomplete; about the same happiness distribution.
Mood diary kept 30 days and repeated interviews and tests during three years.
- Authors's label
- Personality traits
- Our Classification
- 16 Personality Factor Test (16 PF test; see Cattell, 1950).
Observed Relation with Happiness