eClass Support
STACK Quiz Question Performance Update
Posted by Dave Laurie on 23 July 2021 09:54 AM

Attention eClass Instructors,

The recent upgrade to eClass has introduced a new version of the STACK mathematical questions type that has performance implications that will affect any instructors using this question type. We have already emailed affected instructors directly but are also posting a news item to ensure no one is missed.

The new version of STACK has more thorough syntax checking built into the edit question page which will improve performance of questions as they are created going forward. However previously authored questions will need to be reviewed as the new question validation functions can cause a performance slowdown. 

We recommend that all instructors review their questions and follow the guidelines for ‘future proofing’ them outlined here. (This links to in-system documentation so users must be signed into eClass to access it.)

The following steps should be taken for all existing STACK questions:

  • Add semicolons to the ends of all variable and function statements. This is required syntax moving forward.

  • Validate question syntax by clicking 'No variants of this question have been deployed yet' - even without adding variants to a question this can help identify potential problems that existed previously and which may be slowing down the checking function.

  • Deploy variants for any questions that use a lot of random variables as this will speed up the time for students to start the exam by using a pool of pre-created values on launch.

To give a sense of what this will mean practically, in a test exam of 50 STACK questions that ran after the upgrade, the quiz initially took around 30 seconds to load; adding semicolons to all the expressions reduced that launch time to 15 seconds. Adding questions variants shorten this time to ~7 seconds.

Please let us know if you have any questions.

IST eClass Support