Six large school districts that built principal pipelines, a set of measures to cultivate effective school leaders, saw notable, statistically significant benefits for student achievement across their communities, according to this groundbreaking report by RAND. After three years, pipeline-district schools with newly placed principals outperformed comparison schools in other districts by more than 6 percentile points in reading and almost 3 percentile points in math, an unusual accomplishment. “We found no other comprehensive district-wide initiatives with demonstrated positive effects of this magnitude on achievement,” the authors say.  

The pipelines also led to benefits in principal retention, according to the report. After three years, pipeline districts had nearly eight fewer losses for every 100 newly placed principals than the comparison group. This is significant because principal turnover is disruptive to schools and costly, with districts spending an estimated $75,000 to replace a principal. 

(A collection of publications and resources about principal pipelines—including an interactive infographic—is available at www.wallacefoundation.org/principalpipeline.)      

Pipeline-building proved doable and relatively inexpensive for the six districts, suggesting other large districts, too, are capable of building pipelines and seeing a similar, positive impact from the work.  “Our findings show that such efforts undertaken by committed large, urban districts are feasible, affordable and effective,” the authors write.

The report presents the results of research that examined the Principal Pipeline Initiative, a six-year effort supported by The Wallace Foundation and launched in the 2011-2012 school year in Charlotte-Mecklenburg, N.C.; Denver; Gwinnett County, Ga. (outside Atlanta); Hillsborough County (Tampa), Fla.; New York City; and Prince George’s County, Md (outside Washington, D.C.). The “pipeline” refers to four, mutually reinforcing components the districts put in place to seek to boost principal effectiveness: rigorous standards that spell out what their principals are supposed to know and do; high-quality pre-service training for aspiring principals; data-informed hiring; and well-aligned support and evaluation of principals, especially newcomers to the job.

The research compared student achievement test scores in pipeline district schools that received new principals with similar schools, elsewhere in the districts’ states, that received new principals. The findings suggest that a student scoring at the 50th percentile in reading in a comparison school would have scored in the 56th percentile in a pipeline school with a new principal. The positive results were felt districtwide across the participating districts and, to a large extent, across grade levels. Statistically significant, positive benefits in reading and math were seen in both elementary and middle school, while high school saw such benefits in math. In addition, the positive effects kicked in quickly; they were evident in the earliest groups of pipeline initiative principals.

All the districts were able to construct the four pipeline components fully or in good measure by the time the initiative ended in the 2016-2017 school year, although each district took its own approach to the work, reflecting its unique needs and circumstances. The researchers found little correlation between any individual pipeline component and the effects, suggesting that benefits accrue from the pipeline as a whole.

“Districts looking for ways to enhance school outcomes and improve the retention of newly placed principals should be encouraged by the experiences of the [pipeline] districts,” the authors say. “Our findings suggest that when districts focused attention on activities related to principal pipelines, principals, schools and students benefitted.”

The report is part of a  wide-ranging study that includes an examination, detailed in five reports by Policy Studies Associates, of how the districts implemented their work. The study also encompasses an exploration of pipeline spending, with RAND finding that the pipelines cost less than 0.5 percent of the six districts’ annual expenditures on average. A follow-up report, by Policy Studies Associates, looks at the sustainability of the district efforts after foundation funding for them ended. These reports and other information about principal pipelines—including an interactive infographic—can be found at www.wallacefoundation.org/principalpipeline.