Grade sliding scales are intended to provide an graphical indication of student progress in performance scale classes. There are many ways to measure progress, but two common ones are to have students try to achieve "Meeting Expectations" or to become "Proficient".

Simplegradebook uses an algorithm to determine whether a student has attained these achievement levels. The algorithm is described in this FAQ:

http://simplegradebook.ca/smf/index.php?topic=131.0The grade sliding scales use the same algorithm. By comparing the sliding scale to the assignment summary it is clear what level the student is at.

Here are a few examples:

In the above example, the student has less than 50% of their assignments assessed as "Proficient". In this case, the grade level is "Emerging". However, the student is close to having 50% of their assignments assessed as "Proficient", in which case the grade will be upgraded to "Developing". Another way for the student to be assessed as Developing would be to complete the missing assignments and upgrade the "Emerging" assignments to "Developing". The student needs to complete the missing assignments, and correct the assignments which are assessed as Emerging or Developing to get to the next higher grade.

In the above example, the student's progress is a bit better than half-way to "Proficient". The student has 14 "proficient" grades and 12 grades that are less than proficient. To get to "Proficient", the student needs to correct all the assignments that are missing, emerging or developing. The teacher may also later decide to make some of these assignment practice only, in which case the assignments may not require correcting.