Lead testing was in the mainstream news yet again this month after a report gave California a “C+” for its policies to protect children from lead in drinking water at school. In fairness to California, it was one of the only states to receive a “passing” grade, as 22 of the 32 states analyzed received an “F” letter grade. If you’re a parent like me, however, you probably feel like a C+ report card is hardly worth celebrating.

But what exactly did the report base its assessment on?