literary theory

BASICS OF
ITEM RESPONSE
THEORY
THE

FRANK B. BAKER

BASICS OF
ITEM RESPONSE
THEORY
THE

FRANK B. BAKER
University of Wisconsin

Clearinghouse on
Assessment and Evaluation

The Basics of Item Response Theory by Frank B. Baker
Second edition
Published by the
ERIC Clearinghouse on Assessment and Evaluation
Copyright © 2001
ERIC Clearinghouse on Assessment and Evaluation
All rights reserved.
Editors: Carol Boston, Lawrence Rudner
Design: Laura Chapman
Cover: Laura Chapman
Printed in the United States of America
ISBN 1-886047-03-0
(previously published by Heinemann, ISBN 0-435-08004-0)

This publication was set and edited with funds from the Office of
Educational Research and Improvement (OERI), U.S. Department of
Education, and the National Library of Education (NLE) under contract
ED99CO0032. The opinions expressed in this publication do not necessarily reflect the positions or policies of OERI, the Department of
Education, or NLE.

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Acknowledgments
Over the past century, many people have contributed to the development of item response theory. Three persons deserve special recognition. D.N. Lawley of the University of Edinburgh published a paper in 1943 showing that many of the constructs of classical test theory could be expressed in terms of parameters of the item characteristic curve. This paper marks the beginning of item response theory as a measurement theory. The work of Dr. F.M. Lord of the
Educational Testing Service has been the driving force behind both the development of the theory and its application for the past 50 years. Dr.
Lord systematically defined, expanded and explored the theory as well as developed computer programs needed to put the theory into practice.
This effort culminated in his classic books (with Dr. Melvin Novick,
1968; 1980) on the practical applications of item response theory. In the late 1960s, Dr. B.D. Wright of the University of Chicago recognized the importance of the

References: Theories of Mental Test Scores. Reading, MA: Addison-Wesley, 1968. Hillsdale, NJ: Erlbaum, 1980. Department of Education, University of Chicago, 1976. Wright, B.D., and Stone, M.A. Best Test Design. Chicago: MESA Press, 1979.