Are children more successful in early schooling if they have access to full-day pre-k? Westminster Public School District is piloting a new full-day pre-k program to supplement its existing half-day offerings. We will estimate causal effects on student early literacy, special education referrals, and socio-emotional outcomes at the end of the year. We intend to follow study participants through third grade. With colleagues: Daphna Bassok, Vivian Wong.