David Travis • June 5, 2003 (Updated April 21, 2006)
Usability Test Reporting
You know when a profession is mature, because the services and products offered by practitioners share a fair amount of consistency. So for example if I commission two different architects to carry out a house survey, their reports should be pretty similar. One may be cheaper than another, and one may be better able to describe the problems with the roof in terms I will understand, but the problems they find should be consistent.
Usability and variability
Embarrassingly, we have known for a while now that this doesn’t apply to usability testing. The well-publicised work of Rolf Molich shows us that when different usability groups are asked to carry out a web site evaluation, they find lots of usability issues. The problem is that each group finds only a sub-set of all the usability problems. Just one group (of nine) in Molich’s study found more than 25% of the problems. (More detail can be found at Molich’s web site).Given that all these people would describe themselves as “usability professionals”, it’s hard to blame the findings on different skill sets or competencies. A more likely contributor is the fact that the different groups carried out usability testing in a variety of different ways.
So it’s interesting that, during the period of Molich’s work, the US National Institute of Standards and Technology (NIST) initiated an effort to “Define and validate a Common Industry Format for reporting usability tests and their results”. The overall aim of the project was to increase the visibility of software usability.The Common Industry Format (or ‘CIF’ to its friends) isn’t a visual template that helps make usability reports look the same, nor does it tell you how to run a test. However, the framework of the report defines a consistent method of carrying out usability tests. For example, you can only write a compliant report if you take objective usability measures of effectiveness, efficiency and satisfaction (these definitions come from the international usability standard, ISO 9241-11). The report also requires information such as the design of the test (including information about independent variables), data scoring procedures (including operational definitions of usability measures) and details of the statistical analysis used. Following this type of guidance will help ensure consistency and contrasts with the more common approach, where usability tests aren’t “designed”, they just happen. If you are interested in seeing a CIF-style report, Andy Edmonds has recently prepared an HTML version. The CIF became anANSI standard in December 2001 (ANSI/NCITS 354-2001) and became an international standard in 2006 (ISO/IEC 25062:2006 “Common Industry Format (CIF) for usability test reports”). [Article]