Usability – at what cost?

This aspect of interactivity has been one that has changed radically from the early days of IT usability. We used to have to have dedicated usability labs, large numbers of testers, cameras, lights and sound, bells and whistles, belts and braces and so on.

Even Jacob Neilsen, acknowledged veteran guru of the field, has had a very different take on the numbers needed for interactive usability application testing. His latest posting on this makes compelling reading as he advocates five people for the great majority of tests except for certain applications and depending on reasons for testing. The time,effort and numbers involved, let alone dedicated resources like usability labs, mean cost of course, so it is good news that Neilsen’s maximum cost-benefit ratio lines up pretty well with just five test subjects.

Underlying this movement from large expensive tests to small focused ones is a shift away from the onus being put on quantitative research in favour of qualitative research. Yes, I hear your groans! This quantitative versus qualitative debate has dogged art versus science since the academic year dot. However, Neilsen puts a refreshingly simple spin on it.

“... the vast majority of your research should be qualitative – that is aimed at collecting insights to drive design, not numbers to impress people in PowerPoint.”

Jacob Neilsen, June 4th

He goes on to cover some weak reasons why developers are pushed into larger studies and agrees that he himself probably uses more like eight people but gives his reasons. He mentions card sorting. We haven't looked at this specific technique before so what is it?

Card sorting? It is a knowledge elicitation technique for assessing navigation category preferences in interactive applications. This is important when you find that your users are not fulfilling their needs in visiting your site – especially when they can't find the item they wanted to buy, for example. You see the issues. It involves giving testers category headings and asking them to sort them into hierarchies so that navigation preferences can be mapped from use. Remember, insights to drive design. See User Focus for short, uncomplicated answers to your card sorting queries; and Knowhow (non profit), How to use card-sorting to structure your web site, 19th June 2012.

Books have been written about this technique so don't be fooled by the over-simplistic approach to it. If you want more detailed info try Donna Spencer, Card Sorting : Designing Usable Categories, pub. Rosenfeld Media, 2009.