CBM Grade Summary

Quiz reports ::: quiz_cbmgrades
Maintained by argmTony Gardner-Medwin
Quiz Report Plugin showing the appropriate scores when CBM Behaviour has been selected.
Latest release:
272 sites
15 fans
Current versions available: 4

Basic documentation on Certainty-Based Marking (CBM) is at https://docs.moodle.org/en/Using_certainty-based_marking  .

This plugin displays result reports (for teachers) that properly summarise student performance in quiz attempts that use CBM behaviour. Optionally, scores on individual questions can be displayed. Percentages can be calculated on the basis of either just those questions for which a student has entered a response, or the whole quiz. For example, 100% correct on half of the questions - those which the student has chosen to work on - can be shown as 100% rather than 50% correct. This is appropriate when a student uses the quiz for self-testing, choosing just questions relevant to current learning or self-assessment needs.

The plugin was developed alongside improvements in CBM behaviour that are included in core code in Moodle 2.6+. Version 1.2 can be used with Moodle 2.3-2.6. Version 2.7.02 is required for Moodle 2.7 onwards (at least to Moodle 3.0). It really should be in core Moodle.

This plugin doesn't affect feedback of information to students CBM feedback in student Reviews was introduced in core Moodle 2.6, though this is much improved by installing patches (including for earlier versions 1.9+) available at http://tmedwin.net/cbm .

If you want Moodle Grades to correspond to CB Accuracy (0-100%) for comparison with conventional accuracy rather than to the total of CBM marks (see https://docs.moodle.org/en/Using_certainty-based_marking ) then use the code modifications and plugin available at http://tmedwin.net/cbm . Otherwise Moodle Grades range up to 300% based simply on the total CBM marks and have a non-linear relation to conventional accuracy, .

Please report any issues to me: Tony Gardner-Medwin (a.gardner-medwin@ucl.ac.uk)


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Tony Gardner-Medwin (Lead maintainer)
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  • argm
    Mon, Nov 24, 2014, 5:09 PM
    I think (hope) that this wrong installation could only have happened for a short time after 2.7 was introduced. Tony GM
  • argm
    Tue, Nov 25, 2014, 3:49 PM
    Turns out there is a serious problem here. 'Download' gives you the correct plugin version, but 'Install now' always gives the version for Moodle 2.5.
  • argm
    Wed, Nov 26, 2014, 12:48 AM
    Problem solved with new releases (r3) for 2.6,2.7 with amended version.php files and version numbers.
  • Wed, Oct 28, 2015, 5:48 PM
    Hi Tony,

    I used to use the "plus" version of your plugin, but since I upgraded to Moodle 2.9 I cannot find a version that is compatible. Is this in development?

    Many thanks, greatly appreciated.

  • argm
    Fri, Oct 30, 2015, 7:09 PM
    I've added the 'plus' files for 2.88 and 2.9.1-2 at http://tmedwin.net/cbm/moodle/download/ (calculating Moodle grades based on CBM Accuracy). Tony
  • Tue, Jun 28, 2016, 7:42 PM
    I've installed this plugin on a 3.0.4+ instance of moodle and I'm getting the following errors on the feedback page at the end of the quiz:

    "Exception - Call to undefined method quiz_attempt::fire_attempt_reviewed_event()
    Coding error detected, it must be fixed by a programmer: Invalid state passed to moodle_page::set_state. We are in state 3 and state 3 was requested. "

    I followed the instructions for setting up the calculation of CBM; http://tmedwin.net/cbm/moodle/download/

    Other than overwrifgting the modified php files and uninstalling the plug-in how do I fix this?

  • argm
    Tue, Jun 28, 2016, 10:42 PM
    It looks to me as if you used one of the downloads from http://www.tmedwin.net/cbm/moodle/download/ intended for 3.1 rather than for 3.04. Get the right one and replace cbmversion.txt and mod/quiz/review.php . The CBMgrades plugin is not I think the problem.
  • Sat, Jan 26, 2019, 6:52 PM
    Hi Tony,

    I was asked to install this plugin on a moodle v3.5 site, and did so. I'm not a moodle expert in any way, but believe I should find the report under the Grades section when selecting a course. Is this assumption correct? If so, then I'm lost, because the report is nowhere to be found on the site.

    Is it possible for you to explain where I could find the report?

    Kind regards,
  • argm
    Tue, Jan 29, 2019, 2:26 AM
    Riaan - This plugin is to enhance the Quiz Reports visible to staff, not the Summary Grade reports for a whole course. Say if this doesn't solve your problem. Tony G-M
  • Sun, May 26, 2019, 11:17 PM
    Reading your site, I've come to greatly appreciate certainty based marking, and I am eager to deploy it and evangelize it in my teaching. My institution, however, is not willing to incorporate manual patches to the moodle core source code. Is there any way to get 0%-100% marking (accuracy + bonus) without patching?

    Also, any idea if the code distributed at TMedwin.net compatible with 3.7, or will adjustments be needed?

    Thank you for everything you have put into this. You've made moodle a better and more dynamic tool!
  • argm
    Tue, May 28, 2019, 5:10 PM
    (1) The latest standard plugin, essential for staff viewing of CBM grades, should work without changes for 3.7, and this should now be clear on the plugin site.
    (2) The preferred (but more complex, non-linear) grading scheme (0-100%) unfortunately does still require patches to the core code. There have been no reported problems with these patches, but I would need help to get them incorporated into core. Anyone interested? An alternative for student selftests is to use my (non-Moodle) site for CBM selftests: https://tmedwin.net/cbm .
  • Wed, Jun 5, 2019, 6:52 PM
    I can confirm that both the plugin and the "plus" patched code work well on 3.7.

    Though I certainly see the value in a 0%-300% scoring scale, the accuracy+bonus (0-100%) model is going to be an easier transition for many where I work. If there's ever anything I can do to help get the core patched to support both options at the user level, please let me know what I can do to help!
  • Mon, Dec 21, 2020, 11:14 PM
    how can i show number of wrong answers and number of empty answers.
  • Sat, Apr 10, 2021, 4:43 AM
    Just wanted to share feedback that Tony's brilliant CBM work, and specifically the CBM "plus" works brilliantly--tried it out for the first time with my students reviewing for the AP Exams in May and it brings up some really good discussions during class and small group conversations!

    I am running it on 3.8--it's a little tricky to install since you have to change the Moodle core files and need some good admin / Linux skills, which I am no expert but with persistence I finally got it working!

    If there is anyway to make the "plus" code a plugin, or even better make it a part of the Moodle core since CBM is already included in the core, then I think CBM will really take off and more teachers will be willing to try it with their students.

    The feedback and CBM report students get is extremely helpful, and the "plus" code that scales the score based on accuracy and CB bonus is genius!

    Was wondering if the CBM code could also be applied to the adaptive and interactive with multiple tries modes--that would be an extremely powerful 1-2 punch of formative assessment & reflection with real-time instructor delivered hints for the "teachable moment" when students make mistakes as part of the natural learning process!

    I'm seeing students making much better observations and reflections on what they understand--thank you again Tony for sharing your brilliant work with the world!
  • argm
    Wed, Apr 14, 2021, 6:57 PM
    Thanks Joseph! I'm interested in hearing how CBM can best work with school learning, which I don't have experience of. I'm glad it seems to be going well for you.

    Inserting the code mods should be simply a matter of copying all the new files in one operation onto the server, overwriting the standard ones. Backups of the original files are provided in case you want to go back. [I haven't ever used Linux!] But I would be really glad if someone could help get these mods into core Moodle code. I'm not familiar with the protocols, or the (new?) Moodle quiz modes you talk about, since I don't use Moodle myself.
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