Each state has a number of ways to track which students were most impacted by COVID-19 and may be at most risk for increased learning loss. This map shows how many data points states used to triangulate this.
I think this is a case where some states didn’t do a great job reporting what they’ve done to the government. I doubt any state did nothing to locate vulnerable students, but there are many states that failed to report their strategies.
View the map as its own page here.