Assessing cognitive development in a diverse age child cohort using the Mullen Scales of Early Learning and the Kaufman Assessment Battery for Children II: a correlational study among children of adolescent mothers in South Africa

There are significant challenges for research on child cognitive development in resource-scarce environments including the need for contextually appropriate assessments that accommodate diverse age cohorts or span multiple years or rounds of data collection in longitudinal studies. In such cases, combining two cognitive assessments may be necessary to maximize age and assessment item coverage. The Mullen Scales of Early Learning (MSEL) is developed for children aged 2-60 months, while the Kaufman Assessment Battery for Children (KABC-II) is administered to children aged 3-18 years. Understanding the relationship between these scales is essential for drawing valid conclusions across age cohorts and study periods where children may age out of the MSEL. This correlational study examines the relationship between MSEL subscales and KABC-II subtests in a sample of 59 children aged 4-5 years in the Eastern Cape, South Africa using data collected in March-June 2024. Intra-class correlations and paired t-tests demonstrate agreement between the two assessments indicating that the selected subtests are measuring similar underlying constructs. In post-hoc factor analysis the combined subscales had an alpha of 0.86 demonstrating strong agreement between the MSEL and KABC-II. These findings support the comparability of outcomes across different cognitive assessments, enabling researchers to identify risk and resilience pathways for children in low- and middle-income settings.