The socioeconomic achievement gap begins at school entry and widens as children move through school. Many children from low-socioeconomic status (SES) backgrounds do not have access to the material resources or environmental enrichment that would allow them to start school at the same academic level as their peers from high-SES backgrounds. However, a wealth of research supports the potential for high-quality early care and education programs to supplement the cognitive development of students from low-SES families. Low enrollment in high-quality programs and high absenteeism rates can render these children unable to gain cognitive benefits that will prepare them for school entry. This chapter highlights how low enrollment in high-quality early care and education programs and low attendance rates are two overlooked components of dosage that contribute to the small estimates of the efficacy of preschool and the early achievement gap. By understanding these two components of dosage as the outcomes of parents' constrained decision-making, early education policy could be improved.
