Probing the question order effect while developing a chemistry concept inventory

The design of assessment tools is critical to accurately evaluate students' understanding of chemistry. Although extensive research has been conducted on various aspects of assessment tool design, few studies in chemistry have focused on the impact of the order in which questions are presented to students on the measurement of students' understanding and students' performance. This potential impact has been labeled the question order effect in other literature and may be considered as a threat to the construct validity of the assessment tool. The set of studies described in this article tested whether question order effects were present within a concept inventory on acid-based chemistry. In particular, we tested whether the order of two conceptually isomorphic questions, one pictorial and one verbal, affected students' performance on the concept inventory. Two different versions of the inventory were developed and collected from students enrolled in the second semester of first-year university chemistry courses (general chemistry; N = 774) at two different institutions and to students enrolled in the first semester of organic chemistry ( N = 163) at one of the two institutions. Students were further divided in two groups based on their self-reported level of effort in answering the concept inventory. Interviews were also conducted with a total of 19 students at various stages of the studies. Analyses of differences in students' responses to the two versions of the inventory revealed no question order effect in all settings. Implications for instructors and researchers are provided.