Interactive Education Recovery Scorecard shows the difference between 2019 and 2022 test scores in some districts "was essentially zero" while students elsewhere fell much further behind. Scorecard should help superintendents recalibrate their plans to tackle learning loss, say the researchers at Harvard and Stanford universities who conducted the analysis.

Unknowns include how many students are being identified for special education, how many students are awaiting services and whether underqualified teachers are filling vacancies.

Most districts intend to use their resources to provide educators with professional development training and improving their salaries.