The primary reason that so many teachers are out of a job stems from Klein's policy of closing comprehensive high schools, declaring them "failed" enterprises, and replacing them with small high schools.
This limbo world can find a music teacher covering classes for absent social studies teachers, while his music program is assigned to a social studies teacher. I know because this precisely what occurred in my school.
Tenure: tenure for public school teachers is not a lifetime sinecure. In most respects it is no different from civil service protections for police, fire, and sanitation workers. You have to have due process in order to fire an employee.
The once demanding exam was replaced by a ludicrously easy interview and a more questionable statewide written exam.
Mayoral control gave Michael Bloomberg the power to re-establish a Board of Examiners with the stroke of a pen, but nothing has been done to return rigorous standards to the hiring process.
By forcing the principals to figure the real salary of each teacher into their budgets, they have every incentive to hire younger lower salaried teachers and to avoid the more experienced ones, who were too expensive. In Klein's universe inexperience and lower salaries becomes a virtue, while experience be damned!
Around now, you might be asking yourself why the teachers union acquiesced to the ATR? To say that the union has taken a pounding in the press and from the chancellor over the past seven years is an understatement.
In the end, the DOE and the union have been clever by half. Hundreds of millions have been wasted. The hiring process hasn't been improved, and teachers who remain the vital component in the education process are further diminished.