Multiple-select multiple-choice items, or multiple-choice items with more than one correct answer, are used to quickly assess content on standardized assessments. Because there are multiple keys to these item types, there are also multiple ways to score student responses to these items. The purpose of this study was to investigate how changing the type of scoring algorithm applied to student responses to multiple-select multiple-choice items affected both the item difficulty and item discrimination. Responses from elementary- and middle-school level mathematics items on a summative assessment were scored using three methods. Of the many known methods, the three which were examined included dichotomous, partial credit, and multiple true-false. Tests of statistical significance showed mixed results in terms of Classical Test Theory statistics and Item Response Theory parameters. Tables and figures detailing the results overall and by grade level illustrate the dynamic outcomes of three different scoring methods. The information gained through this study can help test developers, educators, and other stakeholders better understand the effects of scoring methods on the measurement of multiple-select multiple-choice items. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]