- 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
- Pysical health
- Our Classification
- Repeated closed question on physical health during the past day, scored eve- ry evening during 6 weeks: very sick / sick / rather poor / fair / good / ex- cellent.