But the devil is in the details, as in the specific combination of factors and conditions that produced the results. When I looked closely at this subset, I was amazed at the array of details that could potentially affect whether quizzes improve learning. Are they pop quizzes or scheduled on the syllabus? What types of questions are used (multiple choice, short answer, etc.)? What’s the relationship between quiz questions and questions on the exam (same questions, similar questions, or completely different)? How many quizzes are given throughout the semester? When are the quizzes given—before content coverage or after? How soon after? Do students take the quizzes in class or online? Are the quizzes graded or ungraded? If graded, how much do they count? Is the lowest score dropped? What kind of feedback are students provided?