Interim Report on the Evaluation of the Growth Model Pilot Project

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The Growth Model Pilot Project (GMPP) was initiated to allow states to experiment with adjustments to the No Child Left Behind Act (NCLB) status accountability system in order to improve the validity of AYP determinations by giving schools credit for students who are making significant growth. The pilot allowed states, districts, and schools to count students who were on track to being proficient (but not yet there). Under NCLB, such students are not counted as proficient for the purpose of AYP determinations.

The pilot was initiated in November 2005 with the goal of approving up to ten states to incorporate growth models in school AYP determinations under NCLB. No longer a pilot, the project was written into regulation in late 2008; now any state may apply to use a growth model meeting certain core principles. Currently 15 states are implementing growth models under this authority: Alaska, Arizona, Arkansas, Colorado, Delaware, Florida, Iowa, Michigan, Minnesota, Missouri, North Carolina, Ohio, Pennsylvania, Tennessee, and Texas.

Main Study Questions

  1. How have states in the pilot implemented growth models?
  2. How does each pilot state's growth model affect the number and kinds of schools that make AYP?
  3. What are the implications of the pilot experience for strengthening the use of growth within the context of NCLB?

Findings and Implications

  • Growth models enabled additional schools to make AYP, but overall percentage increases were not large. The growth models in the eight states resulted in an additional 371 schools making AYP in 2006–07, a 6 percent increase over the number that made AYP under the NCLB status and safe harbor criteria.
    • High-poverty schools were more likely to benefit from the status-plus-growth framework (an 8 percent increase in the number making AYP) than were schools with low poverty rates (a 3 percent increase).
  • The impact of growth models varied widely across states. The percentage increase in the number of schools making AYP due to growth models ranged from 0 to 2 percent in four states to a high of 12 to 14 percent in three states (Florida, Arkansas, and Iowa).
    • Three of the eight states (Arkansas, Florida, and Iowa) accounted for 90 percent of the schools that made AYP solely through growth, and two states (Florida and Iowa) accounted for 71 percent of such schools.
    • In Iowa, 69 percent of the schools that missed AYP under the NLCB status and safe harbor rules were able to make AYP under their growth model. However, in the other seven states, the growth model had a much smaller impact, allowing 0 to 17 percent of schools that would not have otherwise made AYP to do so using growth.
  • Most (but not all) schools that made AYP by status would also have made AYP under the growth model alone. Eighty-five percent of the schools that made AYP under the NCLB status criteria also would have made AYP strictly by using the growth criteria.
    • However, only 45 percent of the Arizona schools that made AYP by status also met the growth criteria. In this state, shifting to the growth model exclusively would have caused an additional 574 schools to miss AYP in 2006–07.
  • Implications for improving use of growth in accountability systems. States could report both status- and growth-based AYP determinations for all schools in order to give a more complete picture of schools' true performance, including both current performance and whether they are on-track to proficiency in the near future.

Study Rationale

The purpose of this study was to determine whether there was any effect, and the kind of effect, of application of the growth models; to provide information about how to strengthen the use of growth under the Elementary and Secondary Education Act (ESEA); and to provide information for states that might consider applying to use a growth model under current regulations. The interim report analyzes the effects of growth models in the first eight states approved under the pilot, for the 2006–07 school year: Alaska, Arizona, Arkansas, Delaware, Florida, Iowa, North Carolina, and Tennessee.

Study Design

The study combined a qualitative description of the Growth Model Pilot Project and the unique mechanisms of the growth models in each of the pilot states, together with quantitative analyses of the increase in the numbers and kinds of schools making AYP under the project and the numbers of schools that could have made their AMOs under a hypothetical "growth only" regimen compared to the numbers of schools that made AYP under the original status-plus-safe-harbor model.

Data Sources

  • To determine how states implemented growth models, the study used information provided by states both in written documentation to the U.S. Department of Education (model proposals, reviewers' comments, decision letters and reviews, and commentary by external groups on models proposed for the pilot program) as well as states' use of growth models for state/local accountability purposes.
  • To determine the effect on the number and kinds of schools that made AYP, the study used data submitted to EDFacts by participating states, as well as additional data supplied directly by the states, to calculate and compare status versus growth-only designations, as well as safe harbor versus growth model designations. It also used school characteristics contained in EDFacts to provide evidence on the extent to which growth models may disproportionately identify certain types of schools as making AYP by growth.

Study Limitations

The data used in the study had a number of limitations. The EDFacts data for 2006-07 only reported growth-model results in terms of how each school was classified for AYP reporting; it did not identify which ESEA reporting groups made their AMOs for reading or mathematics by growth. Also, both school AYP and subgroup AMO results were defined in EDFacts with a set of mutually exclusive categories; thus it was not possible to determine from these data which particular subgroups accounted for their making AMOs as a result of the GMPP growth provisions. These limitations should be corrected in upcoming iterations of EDFacts.

Study Budget

$1.25 million


National Opinion Research Center/NORC at the University of Chicago

Report Date

April 2010

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Last Modified: 01/20/2011