The Hidden Inequity uncovers a silent public health crisis within Scotland’s education system: the creation of unusually wide 19‑month school cohorts that leave the youngest children at a lifelong disadvantage. Drawing on extensive systematic review evidence, policy analysis, and consultation with international experts, the authors show how this cohort structure amplifies relative age effects, shaping children’s mental health, learning disability diagnoses, academic outcomes, physical wellbeing, and long‑term opportunities.

Chapters explore the deeply inequitable impacts of these policies, with girls, children from deprived communities, and minority ethnic groups disproportionately harmed. Well‑intended funding changes have unintentionally widened these gaps, making Scotland’s current system both internationally unique and increasingly unsustainable. The authors argue that this moment presents a rare and urgent opportunity for reform, with legal and financial barriers already resolved and clear evidence pointing the way forward.

Offering nine actionable, evidence‑based policy recommendations, the authors chart a practical path to align school entry with legal ages, tighten cohort structures, improve equity, and bring Scottish practice in line with global standards. A compelling call to action for policymakers, educators, public health leaders, and researchers, The Hidden Inequity reframes school entry policy as a decisive determinant of health and life opportunities.