A new city policy that will place hundreds of teachers without permanent positions back into classrooms this fall has revived a longstanding debate over forced placement — and raised questions about the teachers themselves.

Who are they? What are their track records like? Are they even certified to take open jobs? The truth is, we know very little about the teachers in the pool.

The Absent Teacher Reserve originated with the 2005 union contract between the city and the United Federation of Teachers during Mayor Michael Bloomberg’s first term in office. The contract ended a policy of placing teachers whose positions had been eliminated into other jobs — sometimes forcing other teachers with less seniority out of their schools. Instead, teachers without regular positions were placed in the Absent Teacher Reserve at full salary.

The approach became a problem after school closures and financial recession swelled the pool’s size, and the city has been trying to reduce the pool ever since — through rotating the teachers into temporary positions, offering buyouts and incentives for schools, and now what critics see as a return to forced placement. The city said it would place roughly 400 teachers into vacancies in October. The plan has drawn an outcry from some principals who say it infringes on their authority, and could hurt their budgets.

There’s no way to fully predict the impact of the policy without knowing more about the teachers themselves. The city’s education department and teachers union have been unwilling or unable to share data on the pool, despite multiple Chalkbeat requests. We’ve also filed a public records request with the city that is still pending.

Here are the five main things we’re eager to learn about the current ATR pool.

What is the average years of experience among teachers in the pool?

To estimate the potential impact of an ATR placement on a school’s budget, one would need to know how senior the teachers are.

We know that over the last school year, the ATR pool cost the city a total of $151.6 million, according to the city’s Independent Budget Office. That means, on average, each of the 1,304 teachers in the pool as of last October received $116,258 in salary and fringe benefits. (By comparison, the base salary for a city teacher is $54,000.)

Historically, the ATR pool has been comprised of teachers who are, as a group, more experienced than their peers.

Data from 2010 showed that teachers with 15 to 25 years of experience made up 31 percent of the ATR pool, as compared to 19 percent of all active teachers. In comparison, more junior teachers were underrepresented in the pool — 13 percent, compared to 29 percent of all active teachers.

What percentage of ATR teachers are in the pool for disciplinary reasons?

Unlike the infamous “rubber rooms,” which were used for teachers awaiting disciplinary hearings and were formally phased out under Bloomberg, the ATR pool is not designed for teachers who have been accused or implicated in misconduct. It is meant for teachers whose jobs were eliminated or schools were closed. But some joined after disciplinary proceedings.

A 2014 report from the advocacy group TNTP estimated that 25 percent of teachers in the ATR pool then had been brought up on disciplinary charges.

The Department of Education could not estimate how many teachers now fall into each group. It also has not made clear whether any of the ATR teachers placed into schools this coming fall could have backgrounds of misconduct.

“The DOE has discretion on which educators in the ATR pool are appropriate for long-term placement, and may choose not to assign educators who have been disciplined in the past,” said officials in the city’s education department.

How long have the teachers been in the ATR pool?

Even if teachers are strong performers when excessed from their schools, one principal told us, the time they spend outside the classroom and in the ATR could be harmful, since they are unlikely to receive the same professional development as teachers in full-time positions.

We do not know how long, on average, individual teachers have been in the pool. According to data from the 2014 TNTP report, half of the teachers in the pool at that point had not held a classroom position in at least two years. That proportion is likely to have grown as more teachers have exited the pool on their own, but the city has not made that information available.

Where have ATR teachers worked in the past?

Prior to the city’s announcement that it would be placing teachers from the ATR into classroom vacancies for yearlong positions this fall, ATR teachers were rotated through schools on a monthly basis. “ATRs have been assigned to schools based on short- and long-term need,” city officials said. But we don’t have the list of schools where they were sent.

That matters because some critics have raised concerns that the teachers would be placed primarily in low-income areas of the city, in the struggling schools likely to suffer most from teacher vacancies.

What areas are ATR teachers certified in?

Another question is whether members of the ATR hold certifications that make them difficult to place. Data from 2010 showed that almost 25 percent of ATR teachers then held licenses to teach courses such as swimming, jewelry-making, and accounting, among other subjects that have almost entirely disappeared from public schools.

We do not currently have the breakdown of licenses held by teachers in the pool. That number could be important in showing what percentage of teachers can, realistically, hope to find permanent positions, and how many might need retraining.