Table 1. Baseline Characteristics Across Groups.
| Placebo | AffeCT | |||||
|---|---|---|---|---|---|---|
| M / N | SD / % | M / N | SD / % | t/X2 | p | |
| Age | 14.32 | 2.35 | 14.33 | 2.28 | –0.03 | .975 |
| Gender | 1.41 | .495 | ||||
| Female | 79 | 81 | 80 | 78 | ||
| Male | 16 | 16 | 21 | 21 | ||
| Other | 3 | 3 | 1 | 1 | ||
| Parental education (SES proxy) | 6.31 | .788 | ||||
| General secondary education | 9 | 9 | 8 | 8 | ||
| Advanced secondary education | 14 | 14 | 13 | 13 | ||
| Undergraduate degree | 19 | 20 | 19 | 18 | ||
| Postgraduate degree | 18 | 18 | 21 | 21 | ||
| Missing | 38 | 39 | 41 | 40 | ||
| Ethnicity | 1.43 | .699 | ||||
| Asian | 19 | 20 | 23 | 22 | ||
| Black | 13 | 13 | 18 | 18 | ||
| White | 53 | 54 | 49 | 48 | ||
| Mixed/Other | 13 | 13 | 12 | 12 | ||
| Fluid intelligence | 8.34 | 2.13 | 7.85 | 2.25 | 1.51 | .132 |
| Mental health difficulties | 14.89 | 3.80 | 16.08 | 4.72 | –1.93 | .055 |
| Emotion regulation difficulties | 46.85 | 15.97 | 50.21 | 20.83 | –1.27 | .204 |
| Self-control | 23.82 | 6.52 | 23.04 | 7.25 | 0.79 | .430 |
| Group size | 21.94 | 13.38 | 21.88 | 12.87 | 0.03 | .975 |
Note. The table reports baseline characteristics and demonstrates that randomisation was successful with Bayesian t-tests (continuous variables) and Chi square tests (categorical variables) showing no significant group differences on any baseline characteristics. Fluid intelligence = IQ score derived from the Raven’s Advanced Progressive Matrices (Raven, Court, & Raven, 1988); Mental health difficulties = Difficulties score on the Strengths and Difficulties Questionnaire (Goodman, 1997); Emotion regulation difficulties = Total score on the Difficulties in Emotion Regulation Scale (Gratz & Roemer, 2004); Self-control = Total score on the Brief Self-control Scale (Tangney, Baumeister, & Boone, 2004); Parental education = Highest parental education was measured as a proxy of socioeconomic status (SES); Asian = Included individuals selecting any of these answer options: Asian-other, Bangladeshi, Chinese, Indian, Pakistani; Black = Black is a term used in Britain to refer to citizens of African or African-Caribbean decent, here it included individuals who selected any of the following to describe their ethnicity: Black-African, Black-British, Black-Other; White = here refers to individuals who identified as White-British or White-other; Mixed/Other = here includes individuals who identified as being of mixed or other ethnicity than the available options by selecting Mixed/Other; Group size = average number of participants in the pre- and post-training assessment sessions.