Pondering zeros: analysis of a decade of blanks and missed quizzes

When assessing student work, graders will often find that some students will leave one or more problems blank on assessments. Since there is no work shown, the grader has no means to evaluate the student's understanding of a particular problem, and thus awards 'zero' points. This practice punishes the student behavior of leaving a problem blank, but this zero is not necessarily an accurate assessment of student understanding of a particular topic. While some might argue that this practice is 'fair' in that students are aware that they can't receive points for problems they don't attempt, we share evidence that this practice unequally impacts different student groups. We analyze 10 years of UC Davis introductory physics course databases to show that different groups of students (by gender, racial/ethnic group, first generation, etc.) skip problems, and entire exams at different rates. We also share some implications for grading and teaching practices.