Software Engineering for Usability

2. Cost-justifying usability

There is no free lunch. But sometimes if you eat a good breakfast, you won't need to spend as much money on lunch. Making programs more usable definitely takes a lot of extra time and effort. But this extra cost is usually found worthwhile because of the financial gains due to greater usability. There is a large body of literature on the business-case analysis of HCI methods: (Mantei and Teorey 1988; Nielsen 1993; Bias and Mayhew 1994; Mayhew 1996).

The gains due to higher usability are typically seen from the following factors:

* increased user productivity

* decreased errors

* decreased training costs

* decreased employee turnover

* decreased workplace injuries and lost time

* decreased implementation costs (due to avoidance of late design changes)

* increased sales

* decreased maintenance and support costs

"Faire de la bonne cuisine demande un certain temps. Si on vous fait attendre, c'est pour mieux vous servir, et vous plaire." (from the menu of Restaurant Antoine, New Orleans, as reproduced in (Brooks 1995)) It takes time to produce good, usable software just as it takes time to produce good food. The comparison with fast-food restaurants might imply that standardized software is more amenable to process and predictability -- gourmet quality software demands a skilled chef who is given sufficient time. It's usually worth the wait.

Commercial product development is often driven by the need to get the product on the market as soon as possible. The resulting time constraints seem to discourage use of usability engineering. Lewis and Rieman mention some recent ideas by Peter Conklin (published in (Rudisill, Lewis et al. 1995)):

"The idea is to replace emphasis on time to market by emphasis on time to break even. Many companies measure projects by how quickly they ship. A project that gets to market sooner is rated better than one that takes longer. Conklin points out that the point of getting to market is to make money, and so a more important target date is the time the product recovers its development costs and starts to earn a profit: time to break even. Anything that increases the rate of product acceptance, that is, the growth of sales volume, will shorten time to break even, and if the increase in acceptance is big enough, time to break even may be shorter even if time to market is longer. It's smart to take time to produce a better product if the impact on acceptance is big enough." (Lewis and Rieman 1994).