Calling quality teachers the key to successful schools, Mitt Romney repeatedly focused on measures to retain and reward the highest-performing educators during a NBC's Education Nation Summit.

Romney's remarks solidified his stance in a national debate over the best ways to better evaluate teachers and link those judgments to decisions about hiring, firing and compensation. The recently ended Chicago teacher strike was driven in part by the union's opposition to teacher evaluations drawing on student test scores and to merit pay systems.

“I want the best teachers to be highly compensated," Romney said in response to a question from NBC's Brian Williams. He added that his time as governor of Massachusetts had taught him that classroom size is "a factor, but not a big one. The big one turned out to be the quality of teachers."

President Barack Obama has assailed Romney for promoting a budget that will, according to Obama, slash education spending. In his appearance at the education summit, Romney dismissed the idea that the government can reform public schools by allocating more money.

“We have proven that sending a lot of money to failed schools to pay the same teachers to do the same thing will not make any difference," Romney said, adding that “this is a matter of the leadership of the schools, the quality of the teachers and the incentives that exist for both parents and teachers."

A similar theme emerged as Romney questioned the Obama administration's role in encouraging states to adopt a shared set of curriculum standards, known as the Common Core, by dangling financial incentives.

“I don’t subscribe to the idea of the federal government trying to push the Common Core onto various states," Romney said, adding that "to financially reward states based on accepting the federal government's idea of a curriculum is a mistake," because “there may be a time when the federal government has an agenda it wants to promote."

The Common Core standards were formulated with input from governors and state education chiefs, and the vast majority of states are working to institute them. But Romney responded to a teacher's question about aiding the process by saying “I don’t happen to believe that every time there’s a good idea that comes along the federal government should finance the implementation of that."

“I’m not looking for more federal spending," Romney said. "It is the nature of politics for someone in my position to offer more free stuff. ... I really care about education. I care about our kids so much that I don’t want to saddle them with trillions in new debt when they come out of school.”

Asked about early childhood education programs, Romney questioned the effectiveness of the Head Start program -- an initiative stressed by the Obama administration -- and said the private sector should have a greater role in preparing children for school.

“I don’t think there’s any substitute for the home and efforts to teach people who are having children about the needs of a child and preparing for school and preparing to be educated," Romney said, adding "that is going to happen sometimes at the hands of government and sometimes at the hands of private institutions.”

Romney also enthusiastically promoted charter schools, institutions that receive public funding but are privately run. He said charters are essential to promoting school choice, a traditional tenet of Republican education policy that Romney has backed.

The Obama administration has also promoted charter schools and better teacher evaluations, offering some significant overlap with Romney's agenda. Romney praised the administration's signature education initiative, the Race to the Top program, in which states competed for federal education money by promoting schools reforms.

Many of those reforms promote accountability by relying on student test scores, a key legacy of the 2001 No Child Left Behind law. Romney has questioned that law's role in expanding the federal government's role in education but has praised its use of test scores, and he was "going to keep in place the testing" component.

“You will find throughout your life that there are tests," Romney said to a student who asked if the heavy reliance on testing was harming creativity, "and I don’t know of a way to evaluate the progress of students other than evaluating it through tests.”