Estimating the human development impacts and economic returns from an adolescent cash ‘plus’ programme in Kenya: An economic modelling study

The Government of Kenya plans to scale-up an adolescent-focused cash ‘plus’ programme to improve educational attainment and prevent adolescent pregnancy. We aimed to estimate the programme’s impacts, economic returns, and cost-effectiveness using model-based economic evaluation. We modelled the delivery of conditional cash transfers ‘plus’ adolescent clubs, community conversations, parenting support and psychosocial support to poor adolescents in nine selected counties from 2026 to 2029. Two scenarios were compared: a baseline in which intervention variables remained constant at 2025 levels, and an immediate scale-up sustained throughout 2026–2029. Human development impacts were simulated using an integrated modelling framework. Gains in years of schooling were projected with an education transition model, while reductions in adolescent pregnancy, child marriage, and experiences of violence were estimated with a deterministic age–cohort transition model. Economic returns to schooling were calculated with Mincerian earnings functions. Model parameters were derived from rigorous impact evaluations, nationally representative surveys, and Kenya’s national social registry. The four-year intervention, costing US$46.1 million, is projected to reach 140,000 adolescents, and compared with the baseline, generate an additional 74,900 (+7%) years of schooling; and avert 1,420 (-8%) adolescent pregnancies, 1,500 (-11%) child marriages, 2,970 (-3%) experiences of sexual violence, and 21,800 (-8%) experiences of emotional/physical violence. Furthermore, the intervention is projected to generate US$318 million in discounted lifetime labour earnings, representing a seven-fold return on investment. The estimated cost was US$567 per additional year of schooling, and US$109 when benefits across multiple outcomes were considered, comparing favourably with other adolescent education interventions. Findings were robust to sensitivity analyses, with a >98% probability that returns exceeded programme costs. These findings suggest that scaling up an adolescent focused cash ‘plus’ programme could substantially improve adolescent human development, while delivering strong economic returns and good value for money.