In L.A., inexperienced teachers more likely to be assigned to students behind in math, study says

Teresa Watanabe:

A new study has found that inexperienced teachers in the Los Angeles Unified School District are disproportionately more likely to be assigned to lower-performing math students, perpetuating the achievement gap.
The study also found that L.A. Unified teachers “vary substantially” in their effectiveness, with top teachers able to give students the equivalent of eight additional months of learning in a year compared with weaker instructors.
Such findings raise “deep concerns,” said Drew Furedi, the district’s executive director of talent management, who oversees teacher training. “For us, it’s a call to action.”
The study by the Strategic Data Project, which is affiliated with Harvard University’s Center for Education Policy Research, analyzed the performance of about 30% of L.A. Unified teachers and presented findings based primarily on students’ standardized math test scores from 2005 through 2011 in grades three through eight. The study’s authors acknowledged that test scores were only one measure of teacher effectiveness.
The study also found:
Teacher effects vary substantially in LAUSD, more than in many other districts. The difference between a 25th and 75th percentile elementary math teacher is over one-quarter of a standard deviation, which is roughly equivalent to a student having eight additional months of instruction in a calendar year.
Teach for America and Career Ladder teachers have higher math effects on average than other novices in their first year by 0.05 and 0.03 standard deviations respectively, which is roughly equivalent to one to two months of additional learning. These differences persist over time
The performance of math teachers improved quickly in the first five years, then leveled off.
Those with advanced degrees were no more effective than those without, although L.A. Unified pays more to teachers pursuing such degrees.
Long-term substitute teachers — who have been employed more frequently to fill in amid widespread layoffs — have positive effects in teaching middle-school math

View the complete 1.4MB PDF study, here.
Related: Math forum audio/video.