The D.C. Public Charter School Board released charter-school ratings Wednesday that aim to provide a way to assess and compare education choices across the city.

This is just the second year for the rating system, which scores schools on a 100-point scale. The schools are sorted into high, low and middling performers, based on their students’ progress and achievement on standardized tests, graduation rates and other measures.

Although some schools earned higher or lower ratings than last year, the majority did not change.

Of the 64 campuses assigned ratings, 20 were “Tier 1” high performers, making them eligible for rewards that include priority in competitions for surplus city school buildings and a streamlined process for expanding enrollment.

More than half of the rated charter school campuses — 35 — are rated Tier 2.

“The $10,000 question is how do we help those schools move forward and get better,” said Darren Woodruff, a member of the charter board. “That’s going to be the work this year.”

Nine campuses fell into the bottom tier, making them subject to greater charter board scrutiny and, if performance doesn’t improve, possible closure. The middle grades at the Integrated Design and Electronics Academy (IDEA) Public Charter School scored low enough that the school is automatically a candidate for closure. There is no firm timeline for the charter board to decide whether to close the school.

The charter school board nearly closed IDEA for poor performance last year, but the school survived by promising a radical restructuring: new leaders, new staff and new curriculum.

School leaders argue that IDEA shouldn’t be closed until they have more time to see whether those changes are making a difference. David Owens, chairman of the school’s board, said they hope to be out of the bottom tier within three years.

“We want to demonstrate that the transformation will work,” Owens said.

Last year, a poor ranking led to the closure of the Rand Campus of the Community Academy Public Charter School. Since 2000, 28 charters have been closed for various reasons.

Robert Cane, executive director of the pro-charter group Friends of Choice in Urban Schools, said it is critical that poor performers aren’t allowed to stay open.

“If your results aren’t good after a fair period of time, you need to lose your right to operate,” Cane said.

The rating system is designed to get tougher each year so that schools must improve their performance in order to earn the same score, said Naomi DeVeaux, deputy director of the D.C. Public Charter School Board.

“You can’t tread water and stay a Tier 2 school,” she said. “Each school has to continue to become better.”

There are 102 charter campuses in the city. Those that aren’t subject to standardized testing — such as early childhood and adult education schools — are judged by different standards and aren’t assigned a tier.

The charter board plans to implement a rating system for those schools next year.