BOSTON — New research seems to suggest what many Bay State educators have been saying for a while: the time spent preparing students for testing can degrade the overall quality of teaching.

A new study, that includes two unidentified Massachusetts school districts, found when tougher tests were used in districts that already had higher quality teaching, the test-prep instruction was of a lower quality than regular classroom lessons. President of the Massachusetts Teachers Association, Barbara Madeloni, said an excessive focus on testing necessarily narrows the curriculum.

“In really high-quality educational settings students and educators are all working together to create knowledge, to explore questions,” Madeloni said. “‘Teaching to the test’ really undermines deep learning, deep thinking and student engagement.”

Some supporters of standardized testing argue that tougher tests and more test-prep instruction make for better overall learning. But the study, published in the journal “Educational Researcher,” found that wasn’t the case.

This spring, only half of the state’s third through eighth grade students met or exceeded expectations on the new MCAS tests in Math and English. And Madeloni said they’re hearing from more parents about the incredible pressure testing is putting on students.

“That is so deeply troubling to all of us – that we have lots of evidence that this isn’t working and yet, policymakers seem to be turned off to that evidence, and to the voices of people who are actually living these experiences every day,” she said. “We’ve got to turn that around.”

The Massachusetts Teachers Association is calling for a moratorium on standardized testing. And an Education Reform Review Task Force, formed as part of Senate Bill 308, is examining high-stakes testing in the state.