Correlational finding on Happiness and subject: Age difference among young people

StudyRees et al. (2010): study GB 2010
TitleDeveloping an Index of Children's Subjective Well-Being in England.
SourceThe Childrens Society, 2010, London, UK
URLhttps://www.childrenssociety.org.uk/sites/default/files/tcs/research_docs/Developing%20an%20Index%20of%20Children%27s%20Subjective%20Well-being%20in%20England.pdf
PublicChildren aged 8-15, England, 2010
SampleNon-probability purposive sample
Non-Response
Respondents N =2000

Correlate
Author's labelAge
Our classificationAge difference among young people
Operationalization
age in years from 8 to 15

Observed Relation with Happiness
Happiness
Measure
StatisticsElaboration/Remarks
M-CO-u-mq-v-5-aDM=- p < .001
M dropps from 15.3 in 8-years old to 13.2 in 
15-years old
Set Image size:   

O-HL-?-sq-n-11-aDM=- p < .001
M dropps from 8.4 in 8-years old to 7.3 in 
15-years old


Appendix 1: Happiness measures used
CodeFull Text
M-CO-u-mq-v-5-aSelfreport on 5 statements:

A My life is going well
B My life is just right
C I wish I had a different kind of life
D I have a good life
E I have what I want in life

Rated
0 strongly disagree
1
2
3
4 strongly agree

Shortened Huebner's BMSLSS 'Multidimensional Student Life satisfaction Scale'
(Items left out from original scale are: "My life is better than most young people's" and "I would like to change things in my life)
Name SLSS5
O-HL-?-sq-n-11-aSelfreport on single question:


"overall happiness.."(full question not reported
10 my life is very happy
9
8
7
6
5
4
3
2
1
0 my life is very unhappy


Appendix 2: Statistics used
SymbolExplanation
DMDIFFERENCE of MEANS
Type: descriptive statistic only.
Measurement level: Correlate: dichotomous, Happiness: metric
Range: depending on the happiness rating scale of the author; range symmetric about zero.

Meaning: the difference of the mean happiness, as measured on the author's rating scale, between the two correlate levels.
Source:
Ruut Veenhoven, World Database of Happiness, Collection of Correlational Findings, Erasmus University Rotterdam.
https://worlddatabaseofhappiness.eur.nl