THE DEVELOPMENT OF A DIAGNOSTIC ASSESSMENT OF MOUNTAIN BUILDING PROCESSES

Because of the abstract nature of many Earth science concepts, students often develop misconceptions which differ from scientifically acceptable explanations. Diagnostic assessments have been developed to assess student understanding of life and physical science subjects, but few published assessments diagnose Earth science concepts. The Diagnostic Assessment of Mountain Building Processes was developed to assess students' understanding of the roles of plate tectonics, isostasy and erosion in building and shaping mountains.

Content boundaries of the assessment were defined by establishing a list of propositional knowledge statements based on national science education standards and misconceptions literature. A pilot assessment with multiple-choice items related to the propositional knowledge statements was administered to introductory geology students at Western Washington University. For each answer, students wrote free response reasons explaining their choice. Based on findings from the pilot, two-tier multiple-choice assessments were developed. For each test item, the first tier was a content question and the second tier consisted of reasons selected from students' free responses and literature-documented misconceptions.

Content validity was determined with a specification grid to ensure the diagnostic test items represented the propositional knowledge statements and addressed common misconceptions. The scientific accuracy of assessment items were affirmed by geology professors specializing in tectonics, orogeny, and geomorphology. Essay versions of the assessments were given to some students to compare the frequency and types of misconceptions present in the multiple-choice and essay responses. In addition, in-depth student interviews were conducted with a sample of students to determine how well test responses reflected their actual level of understanding. The diagnostic assessment and validation process revealed several previously unpublished misconceptions about mountain building processes held by introductory geology students. Some of the key misconceptions included: 1) subducting oceanic plate pushes up on continental crust to form mountains, 2) glacial climates are too cold to have high erosion rates, and 3) metamorphic or intrusive rocks are exposed at the surface by volcanism.