Roobrix is a tool that helps teachers avoid grading errors when scoring rubrics. When creating a rubric the lowest level should be minimum expectations, not a zero. Yet when we mark rubrics, the minimum level is 1 out of 4 so the student fails with 25% instead of getting a 50% for minimum work. So instead of failing, the student gets minimum marks. Go to this link to understand more fully. Roobix.com helps you to calculate a rubric more thoroughly, and with more precision. Plug in the numbers that you have given the students, and then it gives out the percent mark. Take a look.