Finland’s PISA performance has continued to slide from the highs of the 2000s, renewing debate over what the country needs to do to lift its education results. According to Yle News, one Harvard professor argues that a stronger focus on teachers and better data collection are part of the answer.

The call comes as Finland looks for ways to understand why its once-celebrated school system has lost ground over time. The professor says collecting more detailed information on teachers would help policymakers identify what is working, what is not, and how to improve the country’s standing in international comparisons.