DELAWARE DEPARTMENT OF EDUCATION GROWTH MODEL INVESTIGATION - A Report of the Growth Model Study Group - December 4, 2024

Oct 15, 2026

Delaware Department of Education GROWTH MODEL INVESTIGATION examines and evaluates student growth measurement models for the state’s accountability system. The report outlines the Growth Model Study Group process, priorities, and the specific models analyzed, including the current DE modified gain scores model, an updated version, and percentile-based approaches (SGP and AGP). It presents evaluation metrics, descriptive statistics, correlation analyses across models 1–4, and additional findings including model-2 supplemental analyses and appendix results.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages53

Reading Time2 h 14 min

AccessFree to download

Executive Summary

Background

Study Group Process

Growth Study Group Priorities for a Growth Model for Delaware’s Accountability System

Models to Study

Evaluation Metrics

Descriptives and Additional Analyses for Model 2

Analysis Results

Model 1: DE modified gain scores model (current model)

Model 2: Updated DE modified gain scores model

Model 3: Student growth percentiles (SGP) model

Model 4: Adequate growth percentiles (AGP) model

Summary and Feedback

References

Appendix 1: Proficiency Indicators

Appendix 2: Additional Analyses for Model 2

Appendix 3: Student-level Growth Metric Distributions

Appendix 4: Student-level Correlations of Growth Metrics with Achievement

DELAWARE DEPARTMENT OF EDUCATION GROWTH MODEL INVESTIGATION: A Report of the Growth Model Study Group December 4, 2024 Will Lorié, Scott Marion, Damian Betebenner National Center for the Improvement of Educational Assessment National Center for the Improvement of Educational Assessment Dover, New Hampshire DELAWARE DEPARTMENT OF EDUCAT ION GROWTH MODEL INVESTIGATION: A Report of the Growth Model Study Group TABLE OF CONTENTS EXECUTIVE SUMMARY ............................................................ 7 BACKGROUND ........................................................................ 8 STUDY GROUP PROCESS ........................................................ 9 GROWTH STUDY GROUP PRIORITIES FORA GROWTH MODEL FOR DELAWARE’S ACCOUNTABILITY SYSTEM................................................... 10 MODELS TO STUDY ............................................................... 11 EVALUATION METRICS ......................................................... 13 DESCRIPTIVES AND ADDITIONAL ANALYSES FOR MODEL 2 ..................................................... 14 ANALYSIS RESULTS ............................................................... 15 • Model 1. DE modified gain scores model (the current model) ............................................................. 15 • Model 2. Updated DE modified gain scores model ........ 19 • Model 3. The student growth percentiles (SGP) model ......................................................................... 23 • Model 4. The adequate growth percentiles (AGP) model ......................................................................... 27 • Evaluation Metrics for Models 1 through 4 ..................... 31 • Study Group Feedback and Additional Analyses ............ 33 SUMMARY AND FEEDBACK .................................................. 37 REFERENCES .......................................................................... 39 APPENDIX 1: PROFICIENCY INDICATORS............................ 40 APPENDIX 2: ADDITIONAL ANALYSES FOR MODEL 2 ........ 42 APPENDIX 3: STUDENT-LEVEL GROWTH METRIC DISTRIBUTIONS....................................................... 47 APPENDIX 4: STUDENT-LEVEL CORRELATIONS OF GROWTH METRICS WITH ACHIEVEMENT ...................... 52 PAGE 2 DELAWARE DEPARTMENT OF EDUCAT ION GROWTH MODEL INVESTIGATION: A Report of the Growth Model Study Group TABLE OF TABLES TABLE 1. Summary of Growth Model Features ...................... 12 TABLE 2. Evaluation Metrics...................................................... 13 TABLE 3. Descriptives of Growth Indicators, Model 1............ 15 TABLE 4. Correlations among School-level Proficiency and Model 1 Growth Indices ................................. 16 TABLE 5. Descriptives of ELA Growth Index by Quartile of Current Proficiency, Model 1 ................................. 17 TABLE 6. Descriptives of Math Growth Index by Quartile of Current Proficiency, Model 1 ................................. 17 TABLE 7. Descriptives of ELA Growth Index by Quartile of Prior Proficiency, Model 1 ...................................... 18 TABLE 8. Descriptives of Math Growth Index by Quartile of Prior Proficiency, Model 1 ...................................... 18 TABLE 9. Descriptives of Growth Indicators, Model 2 (mean-defined, capped variation) ............................. 19 TABLE 10. Correlations among School-level Proficiency and Model 2 Growth Indices ................................. 20 TABLE 11. Descriptives of ELA Growth Index by Quartile of Current Proficiency, Model 2 ................................. 21 TABLE 12. Descriptives of Math Growth Index by Quartile of Current Proficiency, Model 2 ................................. 21 TABLE 13. Descriptives of ELA Growth Index by Quartile of Prior Proficiency, Model 2 ...................................... 22 TABLE 14. Descriptives of Math Growth Index by Quartile of Prior Proficiency, Model 2 ....

FAQs

What is the purpose of the Growth Model Study Group report for Delaware?

The report evaluates student growth measurement models intended for Delaware’s accountability system, detailing priorities, model options, and evidence from analysis results and evaluation metrics.

Which growth models are compared in the analysis results?

The report analyzes four models: the current DE modified gain scores model (Model 1), an updated DE modified gain scores model (Model 2), the student growth percentiles (SGP) model (Model 3), and the adequate growth percentiles (AGP) model (Model 4).

How does the report assess model performance and relationships to achievement?

It provides evaluation metrics plus descriptive statistics and correlation analyses across models, including correlations among school-level proficiency and growth indices and relationships between growth metrics and prior achievement in multiple tables and appendices.

Oct 15, 2026

Uploaded by Taylor Morgan