MatRIC/UK joint colloquium, Newcastle, April 2016

Christian Lawson-Perfect, Newcastle University. @NclNumbas

What is Numbas?

Numbas is an open-source system developed by the e-Learning Unit of Newcastle University's School of Maths and Stats, based on many years of use, experience and research into e-assessment.

It's aimed at numerate disciplines.

It creates SCORM-compliant exams which run entirely in the browser, compatible with VLEs such as Blackboard and Moodle.


Numbas follows the CALM model.

At Newcastle, we used the commercial system i-assess for six years before switching to Numbas.

Development began in 2011 with the aim of replacing i-assess.

Design goals

  • Scalable, reliable and accessible to a broad range of users.
  • Good-looking and easy for students to use.
  • Used by question authors who aren't experts, without support.

Integration with a VLE

Numbas uses the SCORM 2004 standard to integrate with compliant VLEs, such as Moodle and Blackboard.

Or you can use it without a VLE.


A large driver for Numbas was the lack of customisability in previous systems.

Interface and logic are completely separated in Numbas - custom themes can change the look of tests, or reimagine how they're run.

Extensions allow the addition of new functions, data types, and resources.

Formative vs summative use

Computer-aided assessment is great for formative assessment.

Students can try randomised questions over and over until they're happy.

Summative assessment poses problems:

  • How to prevent cheating?
  • Can you ask the right sort of questions for a high-stakes summative exam?

Good formative assessment

Some things to think about:

  • How much more useful is adaptive feedback than a good worked solution?
  • Can you get students to test their own answer before getting feedback from the computer?
  • Apart from marking, what other resources can you give the student? E.g. interactive "toys" to experiment.

Variable generation

Variables are generated declaratively; variables can build on other variables.

The definition interface allows you to work interactively: see generated values immediately, and test for properties.

Adaptive marking

Students kept asking for error-carried-forward marking.

This is complicated to implement, and doubly so when questions are randomised.

Adaptive marking

Solution: when marking a part, replace some question variable(s) with the student's answers to previous parts.

A new "correct" answer is automatically calculated.

It works surprisingly well!

Open access

Compiled Numbas tests are SCORM packages: they're completely self-contained. Perfect for open access resources.

We want to establish a community of authors and users producing quality open-access material.

Public databae

The public database at contains thousands of questions created by hundreds of authors.

Organising such a large bank of questions is difficult!

Several groups run their own instances of the editor.

Version 2

I've been working on a complete update of the editor.

Projects let you collect content belonging to a single course and automatically grant editing access to a group of people.


We're very keen to help others to use Numbas in their courses.

We can do training and provide support, or just help when you get stuck.

Feature requests are also welcome!





Source code