The Strategic Data Project has released the results of an extensive 6-year study that looked at the instructional quality and the environment surrounding around one third of the teachers working in the Los Angeles Unified School District. Among the conclusions published by the authors were that newer teachers are frequently assigned to teach underperforming students more often than their more experienced peers, and that graduates of Teach for America typically have a greater impact on the academic success of their students than new teachers who haven't gone through the program.
The Strategic Data Project, an organization affiliated with the Center for Education Policy Research at Harvard University, has conducted similar studies before in more than 35 districts around the country. The researchers looked at "teacher recruitment, development and retention patterns," not only in traditional public schools but also in national charter organizations. The data collection and analysis had been funded in large part by grants from the Gates Foundation.
LAUSD's report, which was released Wednesday, could become a key resource as the district and United Teachers Los Angeles negotiate changes to teacher evaluations and other parts of the teachers' contract.
The report shines a brighter light on how much of an impact an effective teacher can have on student achievement. Specifically, when measured by student standardized test scores, a teacher who is in the 75th percentile of instructional effectiveness in mathematics provided benefits equivalent to an additional 8 months of schooling over a student taught by a teacher who was at the bottom 25th percentile of effectiveness.
The differences were greater than the average of the other districts studied nationwide, although similar to the differences found in San Diego Unified. The study covered only 30 percent of teachers in the district – those whose students take the California Standards Tests, primarily elementary and middle school teachers. The differences between teachers whose students take the English language arts tests were less pronounced than with math.
To determine teacher effectiveness, researchers applied a value-added method employed by the district: Academic Growth Over Time. In the past, the AGOT model has come under some criticism because it produces results that can fluctuate widely from year to year. However, Jon Fullerton, the director of CEPR, said that it is useful to evaluate data in aggregate, and for comparing large groups of teachers like those that have been in the job for only a couple of years with those who have been in the classroom for a decade or more.
One finding that is likely to draw the attention of administrators overseeing the fiscally-pinched district is that by employing a layoff policy based entirely or mostly on seniority could mean laying off well-performing instructors while allowing those who are not up to snuff to continue working.
In a finding with implications for a state law and district policy requiring layoffs by seniority, the study found that teachers who were laid off in LAUSD as a result of budget cuts were about as effective as teachers who kept their jobs. Since most of the laid-off teachers were less experienced, a slightly higher proportion – 55 percent – were in the bottom two quartiles of performance. However, that also meant that 45 percent of those let go were in the top two quartiles of performers, who, under a more rigorous evaluation system deemphasizing seniority, might retain their jobs.