Comparing Human and Automated Evaluation of Open-Ended Student Responses to Questions of Evolution

Written responses can provide a wealth of data in understanding student reasoning on a topic. Yet they are timeand laborintensive to score, requiring many instructors to forego them except as limited parts of summative assessments at the end of a unit or course. Recent developments in Machine Learning (ML) have produced computational methods of scoring written responses for the presence or absence of specific concepts. Here, we compare the scores from one particular ML program – EvoGrader – to human scoring of responses to structurallyand content-similar questions that are distinct from the ones the program was trained on. We find that there is substantial inter-rater reliability between the human and ML scoring. However, sufficient systematic differences remain between the human and ML scoring that we advise only using the ML scoring for formative, rather than summative, assessment of student reasoning.