In a standards-based grading system, the focus is on students' mastery of specific learning goals rather than traditional percentage scores. That means, rather than grades being determined based on the “percentage correct”, students are assigned a 0-4 based on the level of mastery they have shown in their work ( 0 - no understanding 1 - first steps 2 - partial mastery 3 - mastery 4 - above mastery). It then turns into a percentage
Please note, the percentages do not correspond to the percentage correct, they are simply how the computer calculates the grades. For example, although 3 out of 4 turns into a 75%, it is equivalent to an A for it can only be earned through demonstrating full mastery of the standard (this requires more than 75% of the questions correct).
ACHS Grading Overview:

The 0-4 grading scale is broken up into 5 different levels. Exceeding (4), Mastery (3), Partially Proficient (2), FIrst Steps (1), and No understanding (0).
For a student to be at “Exceeding”, the student is demonstrating a level of understanding ABOVE mastery. The student can use their understanding of the standard to create something new. This is equal to a 4 on our grading scale which in turn is a 100% or an A.
In order to reach “Mastery” the student clearly demonstrated ALL the skills and knowledge required of the standard. This is equal to a 3 on the grading scale. A 3 out of 4 turn into a 75%. However since it is still demonstrating full understanding of the mastery, this too is an A.
In order to reach “Partially Proficient”, the student must demonstrate foundational evidence of the standard with some misconceptions/unfinished learning. This is equal to a 2 on our grading scale which in turn is a 50% or a C..
In order to reach “First Steps”, the student must desmonstrate beginning stages of knowledge and skill. Often it also means they can demonstrate partially proficient understanding with assistance from the teacher. This is equal to a 1 on our grading scale which in turn is a 25% or a D.
Finally, if a student is at a 0, that represents that they have attempted the assignment but have no understanding of standard. A Missing or “M” represents that the student did not attempt the assignment. Both of these result in a 0% or an F unless the student comes in to complete or fix the assignment.