For a decade, the news from the city schools was good. Buildings might be dilapidated, deficits might bring schools to the brink of bankruptcy, and superintendents might be fired, but every summer, educators released test results standing next to charts that showed steady improvement. Baltimore was no longer the worst school system in the state.

But for the past three years, progress — as measured by test scores — has virtually stalled.

Critics of CEO Andrés Alonso say the lack of continued improvement shows that he has failed to make the nuts and bolts of teaching his focus. Another problem, they say, is the constant change within the school system — including high principal turnover — that has marked his tenure.

"He's just not an instructional reformer, and has done nothing to improve teaching since he's been here," said Jessica Shiller, a professor of education at Towson University. "There's been a lot of flip-flopping, moving things around, and turmoil in the system, all in the name of educational improvement. But structural changes, governance changes are just not going to improve achievement."

But other education experts say that such a plateau was expected. Early successes came after the school system made easy fixes, and now leaders must confront the hardest problems of educating children from high poverty neighborhoods with little home support, they say.

School board president Neil Duke said it may be time to assess whether Alonso's reforms have moved the system in the right direction.

"From a policy perspective, everything is going to be on the table," Duke said. "And it is going to be a broad discussion of what we've done, and ... whether our policy decisions have worked."

Alonso acknowledged that his reforms had more impact in his earlier years, and anticipated that sustaining it would be a challenge. He said some initiatives, such as focusing on the most-at-risk students, have tapered off and educators are in a time of transition.

"It's the cycle of improvement," Alonso said. "Once you do radical things that get you a bump right away, and that's not going to continue unless you do things in a completely different way. And we are now at a point where people have to learn to do much harder things."

The reform of Baltimore's schools began in 1997 with a city-state partnership and an infusion of state dollars. Almost immediately there was hope. By 1998, 70 percent of the schools were improving, and third-graders were making progress for the first time in four years.

That progress was documented by test scores nearly every year, on an array of exams from national standardized tests, the Maryland School Performance Assessment Program and then the Maryland School Assessments. In addition, the city's graduation rate improved from 43 percent in 1996 to 72 percent in 2011.

In the early years, educators used increased state funding to make basic changes, such as reducing class sizes, training every teacher in how to teach phonics, and instituting a new math and reading curriculum.The system also standardized instruction so a student who moved from the west to the east side wouldn't be lost.

Alonso took over in 2007 and and for the first two years, the system saw large gains in test scores. He closed 26 failing schools, negotiated a progressive teachers agreement, and allowed principals to control their own budgets and educational programs.

Alonso has acknowledged that some of the gains in test scores were inflated by cheating under his watch. For the past two years the system deployed an army of monitors to ensure test security and accuracy. The result was a decline in scores in 2011, and scores failed to rebound this year.

"The fact that we didn't get a bump this year was disappointing, but it was real, and the progress over time still held," he said.

But some believe that Alonso's first years of gains were actually the fruits of his predecessors' labor.

Jimmy Gittings, president of the city's principals union, said that most superintendents' results are realized two to three years after their reforms. Alonso, he said, is now confronting the impact of his own.

The two superintendents before Alonso — Charlene Cooper Boston and Bonnie Copeland — put programs in place that provided continuity and stability for Baltimore's highly mobile, and challenged students, he said.

"Yes, in the first three years of Dr. Alonso's administration test scores increased, but the reason for those dramatic increases was due to the fact that programs that [Boston and Copeland] implemented were having a positive impact on our children's achievement."