Tierney noted that about 40 percent of the city's foster children are age 17 or older, and those who attended Crooked Places Made Straight were nearing the end of their time in the system and were too far behind to complete high school through traditional means.
She also said that she didn't restrict the youths from attending because they were usually 18 or older and could make their own decisions. Youths age out of the system at age 21.
"The kids who got a diploma there might be delighted," Mirviss said, "but that's very problematic, not only because of its lack of significance and waste of money, but it's also giving the kids a false sense of opportunity and false sense of achievements.
"Its effect is pernicious," he said.
Other advocates say more monitoring is needed of students' progress while in traditional schools, so that they can be better prepared for college.
The department reported in the June court filing that it monitored 89 percent of foster children's educational progress monthly. Mirviss said he contested that number because the department didn't specify what monitoring entailed.
Melissa Rock, child welfare director for Advocates for Children and Youth, said that while the department does a good job of helping students get through the college application process, too many reach that point unprepared after years of moving around.
"To me, this is a matter of making sure there's a lot of oversight of their education because obviously, their lives are so chaotic, it's hard to stay on top of everything," she said. "And I worry about some of these youth who get a high school diploma and start college because they still have to take non-credit courses."
Monisha Cherayil, an attorney with the Public Justice Center Education Stability Project, said foster youths face the same challenges as homeless students because their transience often causes significant disruptions in their educational careers.
She said national research shows that changing schools is equivalent to losing six months of instructional education as the children fall behind.
Cherayil said state law has been strengthened to comply with the federal Fostering Connections to Success and Increasing Adoptions Act of 2008, which sought to improve stability for children who are adopted or in foster care.
Now, Maryland foster care youths don't have to change schools when they change homes, but she said there is still work to be done to keep disruptions to a minimum.
"What we're seeing is there are kids at 17 and 18 who have fallen way behind … and frankly didn't receive all the educational support they could have along the way," Cherayil said. "So the department is left finding quick fixes just as the kids are about to age out.
"Fostering Connections is a first step," she added, "but it remains a work in progress here in Maryland."