Development of early math skills is an important part of elementary schooling and a foundation for continuing progress in not only math, but also science and related subjects. Proficiency among historically underperforming students can show whether districts and education policymakers have made progress in closing the achievement gap between traditionally underserved groups and other students.

In 2019, 59% of students in Lancaster County and 37% of Lancaster City School District students scored as proficient or advanced on the PSSA Grade 3 Math exam, up from 56% in the County and 34% in the District in 2018. In comparison, 44% of historically underperforming students in Lancaster County and 35% of historically underperforming students in the Lancaster City School District passed the exam, up from 40% in the County and 33% in the District in 2018. Lancaster County's 2019 proficiency rate was above the statewide rate for both groups (which was 56% for all students and 39% for historically underperforming students).

Compared with surrounding counties, Lancaster County has the third highest proficiency rate among all students following Chester (68%) and Cumberland (65%) and the second highest performance rate among historically underperforming students following Cumberland County at 45%. Lancaster County's share of historically underperforming students in third grade (55%) is lower than Dauphin (62%) and Berks (61%) and higher than Lebanon (53%), York (52%), Cumberland (41%), and Chester (37%).

As assessments vary among states, it is not possible to include comparable data for the nation or other areas in this indicator. Data are from the Pennsylvania Department of Education.