Correlational finding on Happiness and subject: Self-actualization (need for)

StudyBachman et al. (1978): study US 1966
TitleYouth in Transition, Vol. VI. Adolescence to Adulthood. Change and Stability in the Lives of Young Men.
SourceInstitute for Social Research, 1978, University of Michigan, Ann Arbor, USA
PublicPublic highschool boys followed 8 years from grade 10, USA, 1966-74
Non-Response2.8% at T1, 17.2% at T2, 21.0% at T3, 28.9% at T4, 28.5% at T5
Respondents N =1628

Author's labelNeed for self- development
Our classificationSelf-actualization (need for)
15-item index containing closed questions designed to 
measure the need for self-development. Scale: 1.00 = 
low; 5.00 = high need for self-develop- ment. Assessed 
at T1, T2, T3, and T4

Observed Relation with Happiness
O-HP-g-mq-v-5-atau=+ p < .001
                  Need for self-development
Happiness         T1      T2      T3      T4
T1         tau = +.34    +.19    +.20    +.15
T2         tau = +.21    +.33    +.24    +.22
T3         tau = +.18    +.18    +.32    +.21
T4         tau = +.13    +.15    +.22    +.30
All tau's significant (001)
T1:1966, T2:1968, T3:1969, T4:1970

Appendix 1: Happiness measures used
CodeFull Text
O-HP-g-mq-v-5-aSelfreport on 6 questions:

" Describe the kind of person you are. Please read each sentence, then mark how often it is true for you"
1 I feel like smiling
2 I generally feel in good spirits
3 I feel happy
4 I am very satisfied with life
5 I find a good deal of happiness in life
6 I feel sad

Response options:
5 almost always true
4 often true
3 sometimes true
2 seldom true
1 never true

Summation: average
Possible range: 1 to 5

Appendix 2: Statistics used
tauGOODMAN & Kruskal's TAU
Type: descriptive statistic only.
Measurement level: Correlate: nominal, Happiness: ordinal
Range: [0; +1]

tau = 0 knowledge of the correlate value does not improve the prediction quality of the happiness rating.
tau = 1 knowledge of the correlate value enables a perfect (error-free) prediction of the happiness rating.
Ruut Veenhoven, World Database of Happiness, Collection of Correlational Findings, Erasmus University Rotterdam.