DENVER - Colorado lawmakers Thursday night advanced a bill that would allow parents to opt their children out of standardized tests without facing penalties.

Senate Bill 223, passed a four-hour Senate Education Committee hearing by a vote of 8-1, with only Sen. Mike Johnston, D-Denver, opposing the measure.

School districts and other local education providers would be required to allow a parent to excuse their child from a standardized assessment without facing penalties or repercussion from the state or school district.

Tests such as the controversial Partnership for Assessment of Readiness for College and Careers, or PARCC, would qualify, which falls under federal Common Core standards.

"I am fully supportive of assessments that have value in a student's life ... But this bill is about the authority of a parent to make a decision on behalf of a child," said Sen. Chris Holbert, R-Parker, a co-sponsor.

Sen. Nancy Todd, D-Aurora, another sponsor, added: "I am not anti-PARCC, I am not anti-our standards. That is not the agenda. It is a matter of re-evaluating - is there something we can be doing a little differently?"

The bill comes amid a larger debate at the Legislature and across Colorado and the nation over student testing. A separate bipartisan Colorado measure, SB 215, aims to reduce the amount of tests students take in Colorado.

But that bill has been complicated by politics, with stakeholders calling for an even greater reduction in the number of tests students take, while also tying the issue to teacher evaluations and Common Core.

Many of the proposals stem from the Standards and Assessment Task Force, which was created from legislation last year. Durango schools Superintendent Dan Snowberger chaired the task force.

Lawmakers have so far proposed reducing the number of language arts and math tests at the high school level, and making sure that the state is not requiring any tests in 11th or 12th grades, other than the ACT, which is taken in 11th grade.

They have also proposed streamlining kindergarten assessments and the READ Act, a 2012 law that focuses on K-3 literacy and assessments.

Students in Colorado take nearly 30 tests during their schooling. Supporters of the testing say it is the best way to mark student and teacher progress.

Legislation in 2010, SB 191, tied 50 percent of a teacher's evaluation to student assessments and growth.

Some feel like the opt-out bill erodes the reforms of SB 191.

"This bill does not solve the problem of overtesting," said Leslie Colwell, with the Colorado Children's Campaign. "What gets measured gets changed, but without the information that's provided by assessments ... we are not able to measure and compare student outcomes."

Johnston, who sponsored SB 191, raised fears about impacting federal funding for education in Colorado by passing the measure. He also worries about skewing assessment results for districts if a large number of students opt out.

Johnston ran several unsuccessful amendments to the bill that aimed to keep the current assessment system intact: "You all are knocking down the barn we spent the last decade building," he told bill sponsors.

"How are you going to build or maintain a state accountability system that doesn't have accurate information?" Johnston asked.

But the movement against testing seems only to be growing, with more and more parents raising concerns. Several of those parents told stories of districts threatening them with repercussions for excusing children from assessments. Tales were told of administrators sending students to in-school suspension and prohibiting students from attending class parties after parents opted to excuse their children from tests.

About 93 percent of parents with students at Mancos High School signed a form opting them out of the PARCC test this week, according to The Mancos Times.

"It's gotten out of control between the federal and state governments imposing all the testing; it's getting in the way of the educational process," said Greg Lawler, a member of the Ridgway School District R-2 board in Southwest Colorado, who made the seven-hour drive to Denver with his two children to support efforts at reducing testing and providing parents with more choice.

"I want to support change," he said.