The problems described in this advisory have now been addressed and CLAMP has issued a new advisory. This page is retained for historical reasons but CLAMP now recommends upgrading to 2.8 or 2.9.
CLAMP has become aware of several critical bugs in the Moodle gradebook which were introduced in 2.8. CLAMP recommends that schools do not upgrade to Moodle 2.8 or 2.9 until these bugs have been mitigated. All current versions of 2.8 and 2.9 (as of writing 2.8.6 and 2.9.0) are affected. Please continue reading for a full explanation.
Moodle 2.8 included significant changes to the gradebook. These included, in part:
- A revamped interface for the grader and user reports with improved scrolling and display on all devices.
- A new “natural weighting” aggregation method.
On the whole these are positive changes. CLAMP evaluated the new gradebook at the 2015 Winter Hack/Doc at Occidental College and the participants there thought it much improved on the old gradebook.
It was always expected that certain edge cases such as drop low/keep high and the sum of grades aggregation method would lead to minor variations in calculated grades. This assumption was incorrect. One major institution reported that after upgrading to 2.8 11% of all enrolled students were affected, some in major ways.
For each individual grade Moodle has always stored the maximum points for that item at the time of grading. Thus if a teacher changed the maximum points for an item after issuing grades two students could have different values for maximum points stored. However, this number was not used in calculating a grade: Moodle always presented to teachers and students a grade based on the student’s individual grade and the current maximum grade.
Moodle 2.8 changed this behavior: the individual maximum points are now used to calculate grades. This means that there are now many cases in past courses where student grades appear to change, often dramatically. This has important consequences for grade auditing and will reduce faculty confidence in the gradebook. Any institution which upgrades from a prior version of Moodle to either 2.8 and 2.9 will see these fluctuations.
On clean versions of Moodle 2.8 and going forward on upgraded versions this behavior will cause confusion as the maximum points for a grade item is no longer a constant for all students in a course. Furthermore, the grader report will in places show the current maximum points for a student even when that student’s actual maximum points vary from it. This inconsistency will also undermine faculty confidence in the gradebook.
These are significant issues. We cannot recommend going with either 2.8 or 2.9 until they are resolved. There are three relevant Moodle tracker issues where these issues are being discussed:
- MDL-48618: Unexpected changes on grades after upgrade to Moodle 2.8
- MDL-48634: Changing max points on an already graded item leaves grades in an inconsistent state
- MDL-50432: Grade integrity must be maintained during upgrades
We encourage everyone to add their voice to these discussions, especially MDL-48618. Moodle core needs to hear from those of us who work with faculty every day. They need to understand that grades changing during an upgrade isn’t an acceptable outcome.
CLAMP hopes that Moodle core will address these issues in a satisfactory manner during the next point releases, scheduled for early July. Eric Merrill at Oakland University has developed several patches which supply a way forward. If core does not take them up CLAMP will evaluate including them in the next round of LAE releases, also scheduled for early July. We will also focus on these issues at the forthcoming Hack/Doc at the College of Holy Cross, June 24-26.
If you have any questions please visit the following topic at the CLAMP Moodle Exchange: https://cme.clamp-it.org/mod/forum/discuss.php?d=1708.