GROWTH MODELS - Issues and Advice from the States - A Guide of the Statewide Longitudinal Data Systems Grant Program

Oct 15, 2026

Growth Models presents issues and practical guidance drawn from multiple states’ participation in the SLDS Grant Program working group. It outlines how states review and select student growth model types—such as trajectory, projection, value table, value-added, and student growth percentile—and explains their core purposes, calculations, and intended uses for accountability and instructional decision-making. The guide also summarizes common development and implementation questions raised to the SLDS State Support Team, emphasizing longitudinal data system impacts and best practices gathered between July 2011 and February 2012.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages15

Reading Time38 min

AccessFree to download

Working Group Overview

Support Staff and Member States

Types of Growth Models

Model Uses, Purposes, and Calculations

Trajectory Model

Proficiency Gaps and Time Horizons

GROWTH MODELS Issues and Advice from the States A Guide of the Statewide Longitudinal Data Systems Grant Program July 2012 This product of the Institute of Education Sciences (IES) Statewide Longitudinal Data Systems (SLDS) Grant Program was developed with the help of knowledgeable staff from state education agencies and partner organizations. The content of this guide was derived from ongoing work of a working group on growth models coordinated and facilitated by the SLDS Grant Program’s State Support Team. The views expressed do not necessarily represent those of the IES SLDS Grant Program. Working Group Members William Bonk Colorado Department of Education Juan Copa Florida Department of Education Neal Gibson Arkansas Department of Education Thomas Gillin Pennsylvania Department of Education John Nau Pennsylvania Department of Education Adrian L. Peoples Delaware Department of Education Xiaoping Wang Iowa Department of Education Christopher Woolard Ohio Department of Education Support Staff Jim Campbell SLDS Program, State Support Team Robin Taylor SLDS Program, State Support Team Rosemary Collins SLDS Program Lindsey Huster SLDS Program, Publications Team For more information on the IES SLDS Grant Program, additional publications and resources, or for support with SLDS development or use, please visit [http://nces.ed.gov/programs/SLDS](http://nces.ed.gov/programs/SLDS). | | Type of Growth Model | | | | | | --- | --- | --- | --- | --- | --- | | | Trajectory Projection Value table Value-added Colorado | | | | | | Used by | FL | AR, IA, OH, PA | AR, DE, IA | FL, OH, PA | CO, AR | | Purpose | Compares individual student performance to proficiency and creates trajectory
for student to close achievement gap within 3-4 years | Estimates an
individual student’s
performance in the future based on actual scores from the past | Assigns points to an
individual student based on year-toyear movement towards proficiency
or maintenance of proficiency | Rates schools based on changes
in student perfor
mance that are bet
ter than expected | Provides information about an individual student’s
or a group of stu
dents’ progress to
parents, teachers,
and administrators | | Calculates | Actual or projected growth | Actual or projected growth | Closing of the gap
toward proficiency or maintenance of proficiency (if already proficient) | Growth that is bet
ter than expected | How much relative
growth a student or
group of students made | | Intended use | Rewards growth that is on target with the trajectory | Rewards growth | Rewards growth | Rewards better
than expected growth | Rewards growth | The Statewide Longitudinal Data Systems (SLDS) Grant Program was asked by several states to review current growth models with the goal of determining the impact of different models on longitudinal data systems and capturing some best practices that states are using in the implementation process. From July 2011 through February 2012, representatives from Colorado, Arkansas, Ohio, Iowa, Pennsylvania, Delaware, and Florida participated in a working group session andfollow-up discussions facilitated by members of the State Support Team (SST). 1 This working group allowed states to more easily discuss and share strategies, best practices, and challenges related to the use of growth models. Specifically, these states have provided the following information to the SST in response to questions about their specific growth model(s) related to: • types andpurposes of growth model(s) used; • description of model(s) used; • data elements requiredfor each model; and • issues and barriers experienced during development, implementation, or use. Types of Growth Models All of the participating states are using a type of student growth model for state or No Child Left Behind (NCLB) accountability such as trajectory, projection, value tabl

FAQs

What student growth model types are covered in the guide?

The guide discusses trajectory, projection, value table, value-added, and student growth percentile models, describing how they support accountability and related reporting needs.

How does a trajectory model typically work?

A trajectory model compares a student’s prior test scores to proficiency at a later time, then creates a linear path to close the achievement gap over a defined period (often three to four years for NCLB compliance).

Why did states participate in the SLDS working group?

States joined to review current growth models and assess impacts on longitudinal data systems, while sharing strategies, best practices, and challenges during development, implementation, and use.

Oct 15, 2026

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