Why the IMS QTI standard is so difficult for open math answers



In the past years, we were frequently confronted with the question whether our tools are QTI (Question & Test Interoperability) compliant. The short and simple answer is ”no!” and let me tell you why.

QTI is a standard from the IMS that tries to standardize the way digital tests are structured and checked automatically. Their goal is to make sure that whenever you have a system with a QTI engine in it, you’re (hopefully) able to play the test without problems. The only way to achieve this goal is to restrict the different functions within the standard to a particular bandwidth (as all standards do) and that’s what QTI does. It restricts the functions to a set of around 20 question types and the response processing to a low level script language to cover the basics. If you’re interested, take a look at this excellent IBM post (Explore QTI in Depth) where QTI is explained in more detail.

For multiple choice questions and simple text or number based question types this is fine, because users cannot be very creative in their answers. This leads to the system response to be easily predictable. However, to be able to let your e-learning system adequately respond to open input of mathematical formulas, like our software does, you need a lot more.

One solution to this issue would be to create a QTI question type that allows for remote response processing. This can be done through a more advanced evaluation engine, specified for particular subjects/disciplines using an API. However, because this is the responsibility of IMS and beyond our control, we didn’t want to wait for this. We made our platform LTI (another IMS standard for remote learning) compliant, what does just that. Our software now allows for integration with different software systems (like Learning Management Systems) while, we are still able to provide rich and interactive feedback to our users! This increases the different functions applicable to our web-based platform, as there are many alternatives to the stand-alone use.

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