The real meaning of “highly qualified” teacher may just have gotten a little murkier. A new study by the Hoover Institution at Stanford University has concluded that, on the whole, teachers without certification are just as effective as their certified counterparts. Looking at the standardized test scores of students in New York City, the study found that, by their third year on the job, both uncertified and alternatively certified teachers perform just as well as traditionally certified teachers. The moral, according to the researchers, is that school systems should spend less time focusing on teachers’ certification status and more on their actual performance during probationary periods. Susanna Loeb, a Stanford professor who has conducted a similar—but separate—study, suggested that teachers’ past experiences and educational achievements should be paramount in hiring decisions. “I’m not ready to give up on résumés,” she said.