Table 4.
Representativeness of Sample
| Original TEDS sample | 16 year TEDS sample | Social Networks Questionnaire Invitation sample | Social Networks Questionnaire Response sample | χ2 test/ t-test | p-value | |
|---|---|---|---|---|---|---|
| N families | 13,734 families | 7,723 families | 1547 families | 1215 families (78.5% response rate) | — | — |
| % Female | 50.24% | 52.45% | 60.85% | 63.41% | 133.53 | 6.91e-31*** |
| % MZ | 33.34% | 35.13% | 31.71% | 30.52% | 26.19 | 3.09e-07*** |
| % White | 91.70% | 92.98% | 93.59% | 94.88% | 15.59 | 7.88e-05*** |
| Mean SES composite (SE) | 0.00 (1.00) | 0.17 (0.99) | 0.16 (0.94) | 0.19 (0.93) | 1.12 | 0.26 |
| Mean Life Satisfaction (SE) | — | 5.69 (1.07) | 5.67 (1.09) | 5.69 (1.09) | 0.32 | 0.75 |
| Mean Depression (SE) | — | 3.62 (4.45) | 3.87 (4.69) | 3.79 (4.62) | 1.56 | 0.12 |
Note. Table showing representativeness of sample of TEDS participants who took part in the current study. ***p < 0.001. % female relates to the sex of the individuals. MZ = monozygotic twins. % White = ethnicity of individual reported at first contact. Socioeconomic status (SES) composite is composed of 5 derived variables relating to parent qualifications and employment, and mother’s age at birth of first child, and is standardised at first contact. Life satisfaction is a composite score (ranging from 1 to 7) from the Brief Multidimensional Students’ Life Satisfaction Scale (BMSLSS), measured at age 16. Depression is a composite score (ranging from 0 to 26) from the Moods and Feelings Questionnaire, measured at age 16.
Original TEDS sample refers to the information of all the individuals who were first contacted to take part in the study between 1994 and 1996. 16 year TEDS sample refers to all individuals who completed the main TEDS data collection between 2010 to 2012, when participants were roughly 16 years old. During this data collection, participants completed comprehensive mental health questionnaires, including life satisfaction and depression. Social Networks Questionnaire Invitation sample refers to all the individuals who were invited to take part in the current study, and these invited individuals were selected based on previous indication that they (or their co-twin) used online social media (e.g. Twitter or Facebook). Social Networks Response sample refers to all individuals who completed and returned the postal questionnaire used in this current study. 32 families completed and returned this postal questionnaire but did not complete the data collection in the full 2010–2012 study. Of the participants who took part in the main 2010–2012 data collection, χ2 tests/t-tests were used to statistically compare proportions/means between participants who went on to complete the current study and participants who did not go on to take part in the current study.