The Effect of Class Size on StudentPerformance and Retention at

Binghamton University

Jack KeilPeter J. Partell

Motivation for Study

Preliminary Audit by NYS Comptroller’s Office recommended SUNY Campuses increase class sizes (“faculty productivity”)

Majority of research on subject conducted at elementary & secondary levels

Gauge effect of auditor’s recommendation at Binghamton University

Hypothesis 1: Student Performance

There is an inverse relationship between class size and student performance.

Binghamton University - Institutional Setting

9,300 Undergraduates 2,700 Graduate Students Highly Selective Outstanding retention and

graduation rates Often cited among top universities

in the U.S.

Colleges Within the University

Decker School of Nursing Harpur College of Arts & Sciences Management Watson School of Engineering Education & Human Development

(no freshmen)

Data Sample: Performance

Freshmen entering Fall 1996: First-time Full-time Degree-Seeking

Fall 1996 & Spring 1997 Semester Courses

One record per student per course

Dependent Variable: Grade in Course

End-of-Semester Course Grade Collapse +’s and -’s

Convenience No difference

Assign Numeric Values (0-4)

Distribution of Grades in Sample

A’s = 33% B’s = 39% C’s = 20% D’s = 4% F’s = 4%

(n=9345)

Explanatory Variable: Class Size

End-of-Semester Enrollments Cross-listed Courses Average = 142 Linear versus Non-Linear Specification

Possible Form of Relationship Between Class Size and Grades

Class Size- +

Grade

-

+ Negative Linear

Possible Form of Relationship Between Class Size and Grades

Class Size- +

Grade

-

+ Negative Log

Characteristics of Negative Log

Class Size

GradeNegative Log

10 20 60 70

90

80

7069

Ordered Logit Regression

Categorical Dependent Variable

More than 2 categories Categories are ordered

Model II (Linear) Model IV (Log)n 9,345 9,345Chi-Squared 2,030 2,129Significance .0000 .0000

Variable Coefficient Std. Error Coefficient Std. Error

Constant -2.9800*** .7311 -1.8019** .7401Class Size -.0019*** .0002 -.3221*** .0246EOP Student .0887 .0982 .0168 .0988Management Student -.0452 .0675 -.0411 .0679Nursing Student -.1414 .1249 -.1539 .1258Engineering/Computer Science Student -.5369*** .0693 -.5249*** .0689Age of Student .1296*** .0371 .1232*** .0372Female Student .1890*** .0436 .1792*** .0437Unknown Ethnicity -.1412 .1058 -.1431 .1061Black -.3686*** .1004 -.3882*** .1006Hispanic -.3057*** .0914 -.3164*** .0917Asian -.3048*** .0577 -.3115*** .0577Non-Resident Alien -.4084 .2758 -.4071 .2770TOEFL Test 1.1593*** .1415 1.1770*** .1416High School Rank .0206*** .0019 .0207*** .0019SAT Verbal .0022*** .0003 .0022*** .0003SAT Math .0037*** .0003 .0037*** .0003Science or Math Course -1.1525*** .0576 -1.0771*** .0570Subsection -.7556*** .0905 -1.3707*** .2997Subsection*Class Size .0004 .0006 .1842*** .0634Subsection (Science/Math) -.1224 .1428 1.2803** .5097Sci./Math Subsection*Class Size -.0014*** .0005 -.3058*** .0950

Effect of Class Size on Freshman Grades

0

0.1

0.2

0.3

0.4

0.5

0.6

5 20 35 50 65 80 95 110 125 140 155 170 185 200 215 230 245 260 275 290

Class Size

Pre

dic

ted

Pro

ba

bili

ty

F D C B A

Additional Variables of Interest

Variable Significant? Direction

EOP Students nSAT Verbal y +SAT Math y +High School Rank y +Science and Math y -

Additional Variables (cont’d)

Variable Significant? Direction

Subsection y -Subsection*Class Size y +

Subsection (Sci./Math) y +Sub. (Sci./Math)* Class Size y -

Hypothesis 2: Student Retention

Students with high average class sizes are less likely to be retained.

Data Sample: Retention

Freshmen entering Fall 1996: First-time Full-time Degree-Seeking

Fall 1996 & Spring 1997 Semesters

Dependent Variable: Retention

Check Fall 1997 Enrollment• If yes, Retained = 1• If no, Retained = 0

Distribution:• Not Retained = 9%• Retained = 91%

Explanatory Variable: Average Class Size

Student’s Average Class Size Across Fall 1996 & Spring 1997 Semesters

Average = 99 Linear versus Non-Linear Specification

Linear Model Log Model

N 1221 n 1221Chi-Squared 87.94 Chi-Squared 87.10Significance .0001 Significance .0001

Variable Coefficient Prob.Level

Variable Coefficient Prob.Level

Constant 2.8268 .5102 Constant 5.6162 .2380Average Class Size -.0093 .0153 Average Class Size (Natural

Log)-.8214 .0271

EOP Student -.0053 .9935 EOP Student -.0342 .9580Management Student .6430 .1634 Management Student .6546 .1559Nursing Student 1.1079 .2916 Nursing Student 1.1767 .2613Engineering/Computer ScienceStudent

-.2090 .5976 Engineering/Computer ScienceStudent

-.1674 .6706

Age of Student .1053 .6226 Age of Student .1102 .6057Female Student -.3736 .1271 Female Student -.3866 .1139Unknown Ethnicity .2817 .6361 Unknown Ethnicity .2700 .6474Black .9981 .2289 Black .9738 .2351Hispanic -.5455 .2388 Hispanic -.5554 .2299Asian .0035 .9911 Asian -.0050 .9869Non-Resident Alien -.7111 .5278 Non-Resident Alien -.7029 .5321First-Year GPA (Natural Log) 2.8506 .0001 First-Year GPA (Natural Log) 2.8609 .0001High School Rank -.0150 .2431 High School Rank -.0151 .2393SAT Verbal -.0018 .2713 SAT Verbal -.0019 .2609SAT Math -.0031 .1186 SAT Math -.0031 .1190% Science and Math Credits .8580 .2060 % Science and Math Credits .7248 .2727

Effect of Class Size on Freshman Retention

0.5

0.6

0.7

0.8

0.9

1

5 20 35 50 65 80 95 110 125 140 155 170 185 200 215 230 245 260 275 290

Class Size

Pre

dic

ted

Pro

ba

bili

ty

Additional Variables of Interest

Variable Significant? Direction

EOP Students nSAT Verbal n SAT Math n High School Rank n % Sci./Math nFirst-Year GPA y +

Summary of Findings on Performance

Negative relationship between class size and student performance (grades)

Probability of getting an A decreases at a decreasing rate

Summary of Findings on Retention

Negative relationship between average class size and freshman retention

Probability of being retained decreases at an increasing rate

Contributions of Study

Analyzes effects of class size at a post-secondary institution

Tests the effect of class size on variable other than student performance: retention

Large n analysis

Future Research

Add data from multiple institutions Current results apply to

• Binghamton University only Add faculty variables, e.g., Rank Test sensitivity of results by using

mid-semester enrollments