 Participant numbers are based on power calculations for the intervention studies of the over-arching project which are based on the following assumptions: Power .80; Alpha .05; Medium effect size: d 0.5, f2 .15. The intervention studies are powered to check for an effect of intervention compared to control and to check whether, for participants in the intervention condition, socio-economic status SES explains intervention effect. To test for this, 55 participants per group are needed to compare mean difference scores for intervention and control conditions with an independent t-test, and to run a regression model with difference scores as the outcome measure and SES as a continuous predictor. 