The Department of Education released a final installment of Teacher Data Reports today, for teachers in charter schools and schools for the most severely disabled students.

Last week, the city released the underlying data from about 53,000 reports for about 18,000 teachers who received them during the project’s three-year lifespan. Teachers received the reports between 2008 and 2010 if they taught reading or math in grades 4 through 8.

When the department first announced that it would be releasing the data in response to several news organizations’ Freedom of Information Law requests, it indicated that ratings for teachers in charter schools would not be made public. It reversed that decision late last week and today released “value-added” data for 217 charter school teachers.

Participation in the data reports program was optional for charter schools and some schools entered and exited the program in each year that it operated, with eight schools participating in 2007-2008 and 18 participating in 2009-2010. At the time, the city had about 100 charter schools.

The department also released reports for 50 teachers in District 75 schools, which enroll the city’s most severely disabled students. The number is small because few District 75 students take regular state math and reading exams. Also, District 75 classes are typically very small, and privacy laws led the city to release data for teachers who had more than 10 students take state tests. District 75 also teachers received reports only in 2008 and 2010; the program was optional in the district’s schools in 2009.

Department officials cautioned last week that the reports had high margins of error — 35 percentage points for math teachers and 53 percentage points for reading teachers, on average — and urged caution when interpreting them.

“We would never advise anyone — parent, reporter, principal, teacher — to draw a conclusion based on this score alone,” Chief Academic Officer Shael Polakow-Suransky told reporters during a briefing about the data release.

The reports released today have similarly wide-ranging error margins, and only about 40 teachers received multi-year value-added estimates that are more reliable than single-year estimates.

James Merriman, CEO of the NYC Charter School Center, said in a statement the charter schools that had opted into the city’s value-added system had done so because they “are open to as much information as possible on how their teachers — and schools — are doing.”

But he said charter school leaders were “well aware of the data’s limitations” and found little value in seeing their teachers’ scores made available to the public.

“Publishing this data serves little purpose for the schools or their teachers who are constantly made aware of — and held accountable for — their outcomes,” Merriman said.

Seth Andrew, the founder and head of the Democracy Prep network of charter schools, said he had found value in the city’s data release. In 2010, he learned that the 14 teachers at his school who taught reading and math had posted ratings of “average” to “high” compared to other teachers across the city. But he said he appreciated finding out today how their ratings compared to teachers at other charter schools.

Still, Andrew said, “We dont think any one point of data is enough to evaluate a teacher or a student.” Democracy Prep’s teacher evaluation system are based 40 percent on objective measures such as test scores and 60 percent on subjective measures such as observations, just like the state evaluation framework approved earlier this month.