Time trends and area-level socioeconomic inequalities in early childhood development at 2-2.5 years old in England between 2019 and 2025: a local area ecological study.

INTRODUCTION: There are gaps in national data on early childhood development to inform progress in closing the inequality gap and to capture the impact of the COVID-19 pandemic on children's development in different developmental domains. This longitudinal area-level ecological study examined time trends in socioeconomic inequalities in early childhood development at 2-2.5 years in England's local authorities between 2019 and 2025. METHODS: We included 2 105 384 children from 119 upper-tier local authorities. Rates per 100 children not on track in development at 2-2.5 years, assessed on the Ages and Stages Questionnaire 3, were analysed. Area-level income deprivation was assessed using the Income Deprivation Affecting Children Index 2019, converted to the Slope Index of Inequality (SII) and Relative Index of Inequality (RII). Linear mixed-effect models assessed the fixed effects of year, year2 and income deprivation on early childhood development in any developmental domain and in communication, gross motor, fine motor, personal social or problem solving. RESULTS: The average rate of children not on track in any developmental domain increased from 15.2 (95% CI 13.7 to 16.7) in 2019, peaking in 2023 (19.1 (17.5 to 20.7)), but with little sign of recovery by 2025 (year: 1.09 (1.05 to 1.13); year2: 0.99 (0.99 to 1.00)). Rates for communication, personal social skills and problem solving increased more steeply than gross motor and fine motor. The most versus least income-deprived areas had worse developmental outcomes throughout the period (SII: 5.8 (4.7 to 7.0); RII: 44% (35% to 55%)), with no evidence of year x income deprivation interactions. The largest absolute inequality gap was in communication (SII: 4.7 (4.0 to 5.7); RII: 56% (46% to 72%)). DISCUSSION: In England, early childhood development worsened during the pandemic and children born after the pandemic continue to be affected. Area-level inequalities were striking but did not worsen during this period. Pandemic-recovery efforts need to consider the potentially enormous economic and societal cost of disruption to early childhood development.