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Examination of the Application of Item Response Theory to the Angoff Standard Setting Procedure

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Examination of the Application of Item Response Theory to the Angoff Standard Setting Procedure University of Massachusetts Amherst ScholarWorks@UMass Amherst Open Access Dissertations 9-2013 Examination of the Application of Item Response Theory to the Angoff tS andard Setting Procedure Jerome Cody Clauser University of Massachusetts Amherst, [email protected] Follow this and additional works at: https://scholarworks.umass.edu/open_access_dissertations Part of the Education Commons Recommended Citation Clauser, Jerome Cody, "Examination of the Application of Item Response Theory to the Angoff tS andard Setting Procedure" (2013). Open Access Dissertations. 783. https://doi.org/10.7275/432y-0b36 https://scholarworks.umass.edu/open_access_dissertations/783 This Open Access Dissertation is brought to you for free and open access by ScholarWorks@UMass Amherst. It has been accepted for inclusion in Open Access Dissertations by an authorized administrator of ScholarWorks@UMass Amherst. For more information, please contact [email protected]. EXAMINATION OF THE APPLICATION OF ITEM RESPONSE THEORY TO THE ANGOFF STANDARD SETTING PROCEDURE A Dissertation Presented By JEROME CODY CLAUSER Submitted to the Graduate School of the University of Massachusetts Amherst in partial fulfillment Of the requirements for the degree of DOCTOR OF EDUCATION September 2013 Education © Copyright Jerome Cody Clauser 2013 All Rights Reserved EXAMINATION OF THE APPLICATION OF ITEM RESPONSE THEORY TO THE ANGOFF STANDARD SETTING PROCEDURE A Dissertation Presented By JEROME CODY CLAUSER Approved as to style and content by: ________________________________________________________ Ronald K. Hambleton, Chairperson ________________________________________________________ Lisa A. Keller, Member ________________________________________________________ Penelope S. Pekow, Member ____________________________________________________ Christine B. McCormick, Dean School of Education ACKNOWLEDGMENTS I am profoundly grateful and humbled by the encouragement and guidance I have received throughout the writing of this dissertation. First, I appreciate the support of my committee members, each of whom has made invaluable contributions throughout this process. Penelope Pekow brought the perfect balance of expertise and perspective to the committee. Your careful reading, thoughtful comments, and excellent suggestions have dramatically improved this thesis. Lisa Keller has been a friend and mentor for over four years. Your endless ability to both challenge and support has made me a better researcher, a better thinker, and a better person. Finally, Ron Hambleton has been the greatest, advisor, teacher, and mentor that I ever could have imagined. Your wisdom and insight have been unparalleled as, together, we reexamined what we knew about Standard Setting. I am honored to be able to call you my teacher, and equally honored to call you my friend. In addition to my committee members, I am tremendously thankful for the excellent community of researchers and scholars in the Psychometric Methods program. I feel particularly fortunate that my time at UMass has been shared with a cohort of amazingly gifted and thoughtful students. When I joined the program I did not get to select my peers, but if I had, I would have chosen each of you. I would like to thank my partner, Amanda, who has supported me both emotionally and intellectually throughout this process. I am so thankful to have been able to share this journey with you. I could not have asked for a better partner in psychometrics nor in life. Finally I would like to acknowledge the tremendous support I have received from my parents over the last four years. We have shared in this process in a way that few families could, and I feel truly blessed that you are now able to share in my success. Your love and support are truly appreciated. iv ABSTRACT EXAMINATION OF THE APPLICATION OF ITEM RESPONSE THEORY TO THE ANGOFF STANDARD SETTING PROCEDURE SEPTEMBER 2013 JEROME CODY CLAUSER, B.S. WEST CHESTER UNIVERSITY OF PENNSYLVANIA Ed.D., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Ronald K. Hambleton Establishing valid and reliable passing scores is a vital activity for any examination used to make classification decisions. Although there are many different approaches to setting passing scores, this thesis is focused specifically on the Angoff standard setting method. The Angoff method is a test-centric classical test theory based approach to estimating performance standards. In the Angoff method each judge estimates the proportion of minimally competent examinees who will answer each item correctly. These values are summed across items and averages across judges to arrive at a recommended passing score. Unfortunately, research has shown that the Angoff method has a number of limitations which have the potential to undermine both the validity and reliability of the resulting standard. Many of the limitations of the Angoff method can be linked to its grounding in classical test theory. The purpose of this study is to determine if the limitations of the Angoff could be mitigated by a transition to an item response theory (IRT) framework. Item response theory is a modern measurement model for relating examinees’ latent ability to their observed test performance. Theoretically the transition to an IRT-based Angoff method could result in more accurate, stable, and efficient passing scores. v The methodology for the study was divided into three studies designed to assess the potential advantages of using an IRT-based Angoff method. Study one examined the effect of allowing judges to skip unfamiliar items during the ratings process. The goal of this study was to detect if passing scores are artificially biased due to deficits in the content experts’ specific item level content knowledge. Study two explored the potential benefit of setting passing scores on an adaptively selected subset of test items. This study attempted to leverage IRT’s score invariance property to more efficiently estimate passing scores. Finally study three compared IRT-based standards to traditional Angoff standards using a simulation study. The goal of this study was to determine if passing scores set using the IRT Angoff method had greater stability and accuracy than those set using the common True Score Angoff method. Together these three studies examined the potential advantages of an IRT-based approach to setting passing scores. The results indicate that the IRT Angoff method does not produce more reliable passing score than the common Angoff method. The transition to the IRT-based approach, however, does effectively ameliorate two sources of systematic error in the common Angoff method. The first source of error is brought on by requiring that all judges rate all items and the second source is introduced during the transition from test to scaled score passing scores. By eliminating these sources of error the IRT-based method allows for accurate and unbiased estimation of the judges’ true opinion of the ability of the minimally capable examinee. Although all of the theoretical benefits of the IRT Angoff method could not be demonstrated empirically, the results of this thesis are extremely encouraging. The IRT Angoff method was shown to eliminate two sources of systematic error resulting in more accurate passing scores. In addition this thesis provides a strong foundation for a variety of vi studies with the potential to aid in the selection, training, and evaluation of content experts. Overall findings from this thesis suggest that the application of IRT to the Angoff standard setting method has the potential to offer significantly more valid passing scores. vii TABLE OF CONTENTS Page ACKNOWLEDGMENTS ........................................................................................................................................... iv LIST OF TABLES ........................................................................................................................................................ x LIST OF FIGURES ..................................................................................................................................................... xi CHAPTER INTRODUCTION ........................................................................................................................................................ 1 1.1 The Basics of Standard Setting ..................................................................................................... 1 1.2 The Angoff Method ............................................................................................................................ 2 1.3 The Angoff Method on the IRT Scale ......................................................................................... 5 1.4 Statement of Problem ................................................................................................................... 13 1.5 Statement of the Purpose ............................................................................................................ 15 1.6 Outline of the Study ....................................................................................................................... 15 LITERATURE REVIEW ......................................................................................................................................... 17 2.1 Overview of Literature Review ................................................................................................. 17 2.2 Conceptualizing the Minimally Capable Examinee ..........................................................
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