From The Los Angeles Times: A Times investigation has found that the Los Angeles Unified School District routinely grants tenure to new teachers after cursory reviews -- and sometimes none at all. Evaluating new teachers for tenure is one of a principal's most important responsibilities. Once instructors have permanent status, they are almost never fired for performance reasons alone.
Earlier...from The Los Angeles Times: Los Angeles schools Supt. Ramon C. Cortines has ordered administrators to weed out ineffective new teachers before they become permanent. He acknowledged that the school system has largely failed to adequately evaluate teacher performance.