After finishing a round of usability tests I was interested to read Jakob Nielsen article today, Convincing Clients to Pay for Usability. Particularly interesting was how to handle the question, if you’re a competent designer, why can’t you create a functional web site without having to test it?

Nielsen then lists these analogies, professionals who require (by law or common sense) their work to be tested before public release:

• Software engineers have a test team to catch bugs
• Architects have structural engineers to test their designs, design models for review, computer generated walk-throughs
• Writer have editors to catch grammatical mistakes and structural pitfalls

These projects have a design and test phase in their life cycle. Depending on the type of product, the testing comes either before, after, or during the build phase, whichever will cause the least pain if the design needs to change. With virtually any product, a prototype is built and tested on a sample audience.

Other analogies from the top of my head:

• Advertisers conduct vast market research on the client’s target audience before launching large campaigns
• Biologists go through daunting clinical trials before releasing treatments to the public
• Automobile makers conduct crash tests to reinforce safety in their brands and avoid lawsuits.

Sure, no one will die if the UI doesn’t work, but lack of sufficient testing causing a product recall (called a redesign in the web world) is just as financially devastating and can cause months of perceived online stagnation to customers.

In certain rare cases, design can be a life or death issue. I used to work with some of the original engineers of Microsoft Access. On a customer visit to a government contractor, they were shown how Access was used for the launch sequences of nuclear submarines, each advancing page of the sequence one step closer to nuclear holocaust. Who knows what bugs were lurking in the code—maybe MySQL would have been a better choice?