Test & Measure

Detailed descriptions: critical incident analysis | diagnostic evaluation | expert evaluation | participatory evaluation | performance testing | questionnaires

Overview

The purpose of testing and measuring is to assess the degree to which user and organisational requirements have been achieved, and to provide feedback in a form that can be used by designers and developers to improve the user interface design.

There are a number of different evaluation methods that vary in terms of formality, rigidity and the degree of user participation. The most suitable method will depend on the product being developed, the availability of representative users and financial/time restrictions.

Evaluation can be user based or expert based. User based testing will provide information related to the task at hand - does this design support the user in their work. Expert inspections tend to identify lack of conformity to standards, interface design guidelines and expert comments based on experience.

There are two objectives for testing and measuring:

1. Diagnose usability problems

• user-based methods such as participatory evaluation, diagnostic evaluation, and critical incident analysis should be used when possible, supported by questionnaires to assess attitudes
• these can be supplemented by expert or heuristic evaluation.

These methods should be used to improve early machine prototypes.

2. Evaluate whether usability objectives have been achieved

• requirements for user performance and satisfaction can be evaluated by use of performance testing, cognitive workload and attitude questionnaires.
• other usability objectives can be assessed by expert evaluation.

These methods should be used to test final prototypes. The methods will also provide diagnostic information that can be used to make last minute improvements, or provide requirements for the next release.

In addition to evaluating for usability it can also be beneficial to evaluate the product for pleasure.