13.2 Evaluation Framework

Once the design process has been carried out and a working prototype or the final product is produced, evaluation needs to take place.

The aims of the evaluation are as follows;

Identify and gain an understanding of the various types of users

ighlight usability problems and state how these problems can be resolved

These aims are achieved through the use the following evaluation methods which are discussed in further details;

Cognitive walkthroughs

Heuristic evaluations

13.2 Evaluation Framework

13.2.1 Cognitive walkthroughs

This evaluation method is carried out by an expert in cognitive psychology.

The expert is introduced to the interactive product, having no prior experience in using it and is encouraged to extensively interact with it to try and explore and test all the functions.

This is referred as a 'walk through' as the psychology expert is walking through (extensively using it) the interactive product for the first time.

As he is walking through it, he identifies any potential problems or issues with the design and interaction of the product that could psychologically affect the user in a negative way.

Each interaction by the expert is examined in terms of the impact psychological impact it will have on the user and the mental process that are needed when faced by this interaction.

13.2 Evaluation Framework

13.2.2 Heuristic evaluations

This type of evaluation method is also conducted by an expert, but unlike the cognitive walkthrough where a psychology expert is used, heuristic evaluations are carried out by a HCI expert.

Once a usability criteria is developed by the designers, it is given to the HCI expert to examine the interactive product and see if the product's interaction with the user and design correspond with the criteria.

This type of evaluation looks at the various user interfaces of the interactive product, analyzing and evaluating the technical aspect of them against the usability criteria.

If any problems or issues are flagged up by the HCI expert, the designers are informed.

The usability criteria which is developed by the designers with the aid of the users is a vital document which acts as a guide to the HCI expert in order for comparison and evaluation to take place.

Without this document, this type of evaluation becomes impossible to be carried out.

As well as these evaluation methods carried out by experts, there are other evaluation methods which are carried out by the users of the interactive product, such as focus groups, the use of surveys, field testing and controlled experiments.

These will be discussed in the next lecture.