HTKS measure of executive function and self-regulation: two decades of progress in early childhood measurement.

This review article examines the evolution and impact of a widely used measure of early self-regulation and executive function (EF) in children: the Head-Toes-Knees-Shoulders (HTKS) task. We discuss the importance of SR and EF for children's school success and provide an overview of how these constructs have been conceptualized and operationalized. After situating the HTKS among other SR/EF measures, we trace its development from the original Head-Toes Task, to the HTKS and the HTKS-R and, most recently, the HTKS-Kids digital app and describe how the HTKS has been applied across populations and contexts. We synthesize evidence highlighting its measurement properties (e.g., reliability, validity, developmental change, and associations with academic performance) across diverse cultural and developmental contexts. Special attention is given to the need to extend and validate the HTKS across various educational and practice settings, with an emphasis on the roles of educators in supporting equitable assessment practices. We discuss recent advancements in measurement, including gamified digital administration, adaptations for neurodiverse populations and extensions of the HTKS into adolescence and adulthood. Finally, we identify limitations and directions for research and practice.