Steve Aos & Marna MillerSteve Aos & Marna MillerWashington State Institute for Public Policy

Phone: (360) 586-2740E-mail: saos@wsipp.wa.gov

Institute Publications: www.wsipp.wa.gov

Benefits and Costs of K–12 Education Policies

Evidence-Based Effects of Class Size Reductions & Full-Day Kindergarten

Senate Early Learning Senate Early Learning & K& K––12 Education Committee12 Education Committee

July 11, 2007July 11, 2007

Legislative Direction to WSIPPLegislative Direction to WSIPP

WSIPP: “to begin the development of a repository of research and evaluations of the cost-benefits of various K–12 educational programs and services.”

Reports: “The institute shall provide …by March 1, 2007, a report with preliminary findings; and annual updates each year thereafter.”

E2SSB 5627: Our efforts this biennium will be rolled into the K–12 basic education funding study.

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(From the 2006 and 2007 Operating Budget Bills)(From the 2006 and 2007 Operating Budget Bills)

Prevention programs for youth Early childhood education Juvenile justice Adult corrections and incarceration Substance abuse Mental health Child welfare

Previous Legislatively-AssignedPrevious Legislatively-AssignedWSIPP Cost-Benefit Studies and WSIPP Cost-Benefit Studies and

Evidence-Based Reviews Evidence-Based Reviews

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100%100%

18801880 19001900 19201920 19401940 19601960 19801980 20002000

High School Graduation Rates, United States: 1870 to 2004High School Graduation Rates, United States: 1870 to 2004

The Research QuestionThe Research Question

What Public Policy Levers Lead to What Public Policy Levers Lead to Improved Education Outcomes?Improved Education Outcomes?

Measured K–12 Student Outcomes in the Research Literature

Test Scores High School Graduation Subsequent College Enrollment Subsequent Labor Force Participation Special Education Grade Repetition

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1. WSIPP 1. WSIPP researcher researcher

gathers gathers allall the the studies she studies she

can locate on can locate on a topica topic

2. She applies 2. She applies “standards of “standards of evidence”evidence” to to identify the identify the high quality high quality

studiesstudies

3. She analyzes 3. She analyzes allall of the high of the high quality studies quality studies to estimate an to estimate an average effectaverage effect

Our Research ApproachFirst: What Works to Improve Education Outcomes?

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Our Research Approach (Cont.) Second: What Are the Economics of Each Option?

1. Costs: what does each option cost? For example, we estimate the operating and capital costs to lower class

sizes or fund full-day vs. half-day kindergarten.

2. Benefits: for each option, what is the economic value of any statistically significant increase in education outcomes? We estimate life-time labor market and other benefits (e.g. reduced costs of health care, crime, foster care) of gains in K-12 test score

outcomes.

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3. Compute return-on-investment information & test the sensitivity of the results.

Class Size Reductions

&

Full-Day Kindergarten

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Does Reducing Class Size Improve Test Scores?Does Reducing Class Size Improve Test Scores?

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K 1 2 3 4 5 6 7 8 9 10 11 12Grade in Which Class Size is Reduced

* Effect Size Metric: the change in the standard deviation of test scores on standardized tests.

The Change in Test Scores for a One Unit Drop in Class Size*

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The results of 38 statistically-sound studies (with 69 grade-level tests) of the effect of class size reductions on test-score outcomes.

Each circle is the result from a study

Does Reducing Class Size Improve Test Scores?Does Reducing Class Size Improve Test Scores?

K to 2 3 to 6 7 to 8 9 to 12

Grade When Class Size is Reduced

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No Change

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The Change in Test Scores Per Class Size Reduction*

* Effect Size Metric: the change in the standard deviation of test scores on standardized tests. Boxes are the average effects; vertical lines are 95% confidence intervals.

Multivariate results

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95% Confidence Interval

1. Do Class Size Reductions Boost Test Scores? The results are mixed, they vary by grade level:

Yes, in K through grade 2. Yes, (but less so) in grades 3 through 6. Apparently not in middle and high school (more research needed).

Bottom Line: Class Size EffectsBottom Line: Class Size Effects

2. What are the economics? A one-unit drop in class size costs about $220 per student per year (operating and amortized capital costs). For K-2, the return on investment (ROI) is 8.3% (range 5.7 to 11%). This is equal to $2.79 in benefits per dollar of cost. For grades 3 through 6, the ROI is 6%. For middle and high school, return is negative.

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3. Additional Tentative Finding: Low-Income Students Benefit More from Reductions in Class Size.

Does Full-Day K Improve Test Scores?Does Full-Day K Improve Test Scores?

K 1 2 to 3 4 to 5

Grade When Effect Size Was Measured

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No Change

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The Change in Test Scores Compared to Half-Day K*

* Effect Size Metric: the change in the standard deviation of test scores on standardized tests. Boxes are the average effects; vertical lines are 95% confidence intervals.

The results of 23 statistically-sound studies with 32 grade-level tests of the effect of full-day K on test-score outcomes.

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1. Does full-day K improve test scores? Effects are significant at the end of kindergarten… But they erode quickly between grades 1 and 3

Full-Day v. Half-Day K ConclusionsFull-Day v. Half-Day K Conclusions

3. What are the economics of full-day K? Moving from half-day to full-day K costs an additional $2,611 per student. To generate long-term net benefits, public policies need to examine how to sustain the early gains from any investments in full-day kindergarten. Experimentation seems warranted.

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2. What about disadvantaged students? Test score gains at the end of K are about the same and benefits erode at about the same

rate.

Thank You

Questions?

Washington State Institute For Public PolicyWashington State Institute For Public Policy

Created by the 1983 Washington Legislature

Mission: carry out non-partisan research on projects assigned by the legislature or the Institute’s Board of Directors

Senator Karen Fraser Secretary Robin Arnold-Williams, DSHS Representative Fred Jarrett Director Victor Moore, OFMRepresentative Phyllis Kenney Sandra Archibald, University of WashingtonSenator Jeanne Kohl-Welles Andrew Bodman, Western Washington Univ.Representative Skip Priest Robert Rosenman, Washington State Univ.Senator Pam Roach Les Purce, The Evergreen State CollegeRepresentative Helen Sommers Ken Conte, House Office of Program ResearchSenator Mark Schoesler Richard Rodger, Senate Committee Services