The Host Pathogen Concept Inventory (HPI CI) was developed by the HPI Teaching team (20 research and teaching faculty) as a way of measuring the effectiveness of various curricular initiatives within the University of Maryland (UMD) microbiology degree program. It is an online instrument that consists of 18 multiple-choice questions validated through an iterative process. The concepts covered by the HPI CI align with the Vision and Change Core Concepts and the ASM Microbiology Curriculum.
The multiple-choice format of the HPI CI facilitates quantitative analyses. After students answer each multiple-choice question, they are asked to write an explanation for the answer they chose. These open-ended explanations are highly informative and provide a source of data for understanding student thinking and revealing student alternative conceptions. We have administered the HPI CI in 4-6 courses each semester. Since 2006, we have collected pre- and post-course CI responses from approximately 7000 students enrolled in 9 different courses that are components of the UMD microbiology undergraduate program. Through the quantitative analysis of multiple-choice questions, we measured the impact of innovative teaching approaches. We found that students are making significant progress in their learning in individual courses and retain knowledge as they progress to upper level courses.
By supplementing this analysis with demographic data, we determined that students who had completed a prior course in genetics had significantly higher scores than those who had not. With this insight, we developed a new version of introductory microbiology that has a genetics course pre-requisite and is specifically targeted to biology majors. By offering separate microbiology courses for students with and without previous background in genetics, it has become possible to tailor course content more appropriately to students’ depth of background knowledge.
We also developed a method to mine HPI CI open-ended explanations for alternative conceptions. This process involved working in teams to read and categorize student responses to one CI question, which has resulted in the identification of 20 alternative conceptions relating to the evolution of antibiotic resistance. Analysis of additional questions is continuing. Our approach serves as a “bridging the gap” exercise that informs faculty about the distinctions in their way of thinking in comparison to student or novice thinking. With this awareness of student alternative conceptions, faculty are better able to design interventions to help students gain conceptual understanding.
We have also found that the CI is a good tool to foster cross-institution conversations on student learning through a collaboration with faculty at Virginia Tech.