Optional Extended-Day Kindergarten benefits students above and beyond non-Optional Extended-Day kindergarten. While OEK students began the 2009-10 school year with significantly lower scores than non-OEK students, by the end of the year OEK students had closed this achievement gap and scored similarly to non-OEK students. In some cases OEK students surpassed the achievement of non-OEK students at the end of the year. Thus, this report shows that the program benefits at-risk students. Quick facts include: (1) Approximately 18% of kindergarten students participated in an extended kindergarten program in 2009-10; (2) OEK classrooms gained an average of 54 percentage points over the year; non-OEK classrooms gained an average of 36 percentage points; (3) Significantly fewer OEK students were at risk for falling behind in reading at the end of the year than at the beginning of the year (35% to 13%); (4) A higher percentage of OEK students are able to move up from being at risk compared to non-OEK students (22% compared to 2%); (5) In some districts, OEK classrooms even surpassed the achievement of non-OEK classrooms at the end of the year; and (6) This report finds similar outcomes to the 2009 report on OEK student achievement, and both reports conclude that while OEK students begin the year behind non-OEK students, by the end of the year this gap is closed or surpassed. (Contains 4 figures and 3 tables.)