THE UNDERPINNINGS OF THE DEVELOPMENT OF AN INSTRUMENT TO MEASURE BIOGEOCHEMISTRY CONTENT KNOWLEDGE

Biogeochemistry studied the flow of matter and energy through all parts of the Earth system and an understanding of basic biogeochemistry is a key component of Earth System Science. Despite the importance of biogeochemistry in understanding the Earth system and global change, it often is not explicitly included in undergraduate geoscience curriculum and no instrument exists to evaluate biogeochemistry content knowledge. We developed the Biogeochemistry Concept Inventory (BGC CI) to assess undergraduate students’ biogeochemistry content knowledge. This study aims to overview the development of the instrument as well as to discuss the piloting and validation of this instrument. The instrument was developed using previous qualitative and quantitative data collected from student interviews and consultation with experts to develop a table of specifications. The piloting and validation of the instrument were completed using Amazon’s Mechanical Turk and responses were analyzed using both Classical Test Theory and Item Response Theory. This study will explore both the qualitative and quantitative underpinnings of the development of the BGC CI and how Classical Test Theory and Item Response Theory will be applied in validation of the instrument.