Effect of Violating Unidimensional Item Response Theory Vertical Scaling Assumptions on Developmental Score Scales

Abstract

To my little butterfly, Chantel Without whom I never would have had the strength to get this far iii ACKNOWLEDGEMENTS This dissertation is what it is today because of the many individuals who supported me during this journey. I first need to thank my husband, Joe. You laughed with me in the good times, and you struggled with me in the bad times. You lived with me, and you brought out the best in me always. You comforted me when I was downhearted, and you shared in all of my accomplishments. And for you I am the most that I can. You, Chantel, and Hailey were with me the entire time and words cannot describe how thankful I am to the three of you.

Decision consistency and accuracy indices for the bifactor and testlet response theory models

“…Several sources were examined to determine item parameter distributional parameters (CDOE, 2008;Tong, 2005;Topczewski, 2013;Wainer et al, 2007;Wang et al, 2005). From these studies, the item discrimination parameter, , ranged from 0.8 to 1.3 with a standard deviation of 0.3.…”