In Los Angeles Unified, new teachers get the weakest students, reports a six-year study by the Strategic Data Project.
The study also found “significant disparities in effectiveness among the district’s elementary and middle school teachers, as measured by students’ standardized test scores,” notes EdSource Today.
Researchers found that the difference between a math teacher in the 75th percentile – those whose students performed better than three quarters of other students – and a teacher in the 25th percentile was the roughly equivalent benefit to a student of having eight additional months of instruction in a calendar year (technically one quarter of a standard deviation).
New teachers hired through Teach for America and the district’s Career Ladder program that helps aides become teachers were more effective in math than other novice teachers by two months for TFA and one month for former aides. However, most TFA teachers leave after two years, while Career Ladder teachers usually stay for the long haul.
Forty-five percent of laid-off teachers ranked in the top two quartiles in effectiveness, the study found. All layoffs are based on seniority.
Los Angeles teachers with advanced academic degrees earn more, but are no more effective, the study found. However, “teachers with a National Board Certification outperform other teachers, by roughly two months of additional math instruction and one month of additional ELA instruction over a year.” Most board-certified teachers in Los Angeles work in high-performing schools.