In other online test-building services we use in our program, First Attempt score is an option under Allow Multiple Attempts. This option works beautifully for our self-paced, competency-based training. Because all our courses are 80 percent competency based, the students must achieve 80 percent on testing before moving on. We want each student to have multiple attempts but be motivated to study and be prepared for that "first-time" attempt. Most of our students meet the 80 percent competency on the "first attempt" quiz, but some individuals need to be able to retake a quiz to prove the 80 percent competency. If the student retakes to prove competency, instructors still want to retain the First Attempt for grading.
This idea has been developed and deployed to Canvas