As a demonstration site designated by Oregon as a prime example of “response to intervention” in action, the Tigard-Tualatin district has had to pare visiting groups down to no more than 25 people.

Identifying struggling students wasn’t an issue for teachers at Lynnville-Sully Elementary School, tucked away in this town of 900, an hour’s drive east of Des Moines. Knowing what to do next was the ...