Thousands of students across the country are opting out of standardized tests aligned to the controversial standards of Common Core, which serves to evaluate and help states improve academic performance.

The "opt-out" movement is gaining in momentum in many parts of the country, especially in New York where some superintendents are reporting that 60-70 percent of their students are refusing to take the exams.

According to the anti-testing group United 2 Counter the Core, the number of New York state students opting out of the Common Core English exam reached 155,237 as of Thursday, reports The New York Daily News. In comparison, the New York state education department stated that last year around 49,000 or 4 percent of students didn't take the English test, while 67,000, or 6 percent of students, chose not to take the math exam.

Proponents of standardized tests, however, argue that the test hold schools accountable for their students' improvement.

Assessing every student each year "gives educators and parents an idea of how the student is doing and ensures that schools are paying attention to traditionally underserved populations," U.S. Department of Education Spokeswoman Dorie Nolt said, reports The Associated Press.

Likewise, Merryl Tisch, chancellor of the Board of Regents in New York, released a recent statement, saying, "Those who call for 'opting out' really want New York to 'opt out' of information that can help parents and teachers understand how well students are doing."

Notable resistance is also taking place in states like Maine, New Mexico, Oregon and Pennsylvania. Meanwhile, almost 15 percent of high school juniors in New Jersey opted out of the test this year.

Monty Neill, executive director of the testing reform advocacy group FairTest, says the "opt-out" movement has grown due to an increase in the number of parents who believe that their children are being over tested.

"There've been a number of surveys in states as well as national surveys that are showing (frustration with testing) as a reaction among parents and the public generally, so there's a sense that this testing has just gone round the bend," said Neill, a former educator and school administrator, reports CNN.