Measuring Principals' Effectiveness: Results from New Jersey's Principal Evaluation Pilot

Publisher: Washington, DC: U.S. Department of Education, Institute of Education Sciences, National Center for Education Evaluation and Regional Assistance, Regional Educational Laboratory Mid-Atlantic
May 12, 2015
Christine Ross, Mariesa Herrmann, and Megan Hague Angus

Key Findings:

  • The developers of the principal practice instruments used by pilot districts provided partial information about the instruments’ reliability (consistency across raters and observations) and validity (accurate measurement of true principal performance).
  • Principal practice ratings varied across the possible score range in the pilot year, indicating that the measures have the potential to differentiate performance among principals; however, most principals received ratings of effective or highly effective.
  • School median student growth percentiles, which measure student achievement growth during the school year, exhibit year-to-year stability even when the school changes principals. This may reflect persistent school characteristics, suggesting a need to investigate whether other evaluation measures could more closely gauge principals’ contributions to student achievement growth.
  • School median student growth percentiles correlate with student disadvantage, a relationship that warrants further investigation using statewide evaluation data.

States and districts across the country are implementing new principal evaluation systems that include measures of the quality of principals’ school leadership practices and measures of student achievement growth. But there is little evidence about whether these measures provide accurate information about principals’ performance.

This study, conducted for the Regional Educational Laboratory Mid-Atlantic, finds both strengths and limitations in the measures used for New Jersey’s principal evaluation system. New Jersey conducted a pilot of its principal evaluation system in 14 school districts in 2012/13. The study’s analyses of pilot data indicate that principal practice ratings and schoolwide student achievement growth vary across principals and thus have the potential to distinguish effective and ineffective principals. However, schoolwide student achievement growth changed little at schools that changed principals and was lower at schools with more disadvantaged students. The developers of the principal practice instruments provided only partial information about the accuracy of the scores produced by these instruments.

Information about the properties of the evaluation measures can inform modifications of the principal evaluation system or revisions to the guidance that the state provides districts.


Mathematica Leads the Regional Educational Laboratory (REL) for the Mid-Atlantic Region


U.S. Department of Education, National Center for Education Evaluation
U.S. Department of Education, Institute of Education Sciences

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Mariesa Herrmann
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Christine Ross
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