Evaluating teachers based on student performance is one of the most controversial issues in education today. Pre-K to 3rd grade teachers have been exempt from this scrutiny, since their students don't take standardized test.

A new report by the New American Foundation looks at whether these teachers should also be evaluated based on student achievement.

“Research has confirmed, time and time again, that the quality of instruction and the quality of learning opportunities in children’s formative years sets the foundation for their success as students, and, later, their success as adults,” said Laura Bornfreud, the report's author.

The report, “An Ocean of Unknowns. Risks and Opportunities in Using Student Achievement Data to Evaluate PreK-3rd Grade Teachers,” stopped short of giving a recipe for how evaluations should take place.

It's more complex in these early grades. The report lays learning and other development students should pick up by the third grade: not just literacy and numeracy, but also social-emotional, physical and cognitive skills.

“Determining growth measures for these grades is among the most complex pieces of teacher evaluation reform,” Bornfreud said. It’s hard enough to devise a test to see what a preschooler has learned, let alone use such a test to then accurately evaluate the teacher.

The report breaks down the ways different states and school districts approach student and teacher assessment, finding “opportunities” and “risks” with all approaches.

Study authors mapped which states have upgraded their teacher evaluation policies since 2009. California is in the minority of states that have not upgraded standards in several years.

One of the report’s conclusions is that any system where teachers set goals and measures for students' growth when the teachers compensation and jobs depend on the outcome of those measures "is rife with problems."