Like many districts across the country, Prosser School District in Washington experienced a drop in elementary ELA proficiency during the pandemic. One of the district’s main strategies was to focus its efforts on supporting students performing at the lowest levels. It’s working!

In 2021–2022, Prosser piloted ARC’s Dual Language ARC Core® in grade 5. After a successful year, they expanded the implementation district-wide across grades K–5, and the data shows consistent improvement.

Results from the Smarter Balanced Assessment (SBA) reveal a steady decline in the percentage of students scoring at the lowest performance level. Meanwhile grades 3-5 saw a 13 point, 17 point, and 9 point decrease respectively.

Data from ARC’s Independent Reading Level Assessment (IRLA) shows even more momentum. At the start of the 2022–2023 school year, 56% of students in grades K–5 were reading significantly below grade level in English. By February 2025, that number had dropped to just 25%. The same trend was observed in Spanish, with the percentage of students significantly below grade level falling from 61% to 27%.

What’s driving this improvement? Prosser’s strategy has been clear and focused:

• Start with a targeted pilot: Grade 5 teachers tested the curriculum first, providing early feedback.

• Expand based on results: After a successful pilot year, the district scaled ARC Core across grades K–5.

• Focus on the most struggling students: Instruction and support were designed to close gaps for students performing at the lowest levels.

• Monitor progress closely: Regular assessments in both English (IRLA) and Spanish (ENIL) helped teachers adjust their instruction in real time.

• Sustain momentum: Fewer students are starting school significantly behind each year which shows lasting impact on the district. Take a closer look at their progress by reading the full district profile here: Prosser School District (WA) District Profile May 2025