Foundation Shifts Tack on Studies

Scholars say Gates risks losing valuable findings.

Five years into an eight-year study of its high school improvement efforts, the Bill & Melinda Gates Foundation is shifting its strategy for evaluating the $1.3 billion grant program.

The foundation’s initiative, which is underwriting change efforts in more than 1,800 schools, is the nation’s largest privately funded attempt to improve high schools. Initially focused on creating hundreds of smaller, more personalized schools and schools-within-schools, the program now encompasses a more complex mix of policy measures to reform high schools.

Gates’ decision to halt the study worries some scholars, who say the field will lose valuable insights into an...