The latest issue of interactions magazine, contains Dennis Wixon’s “Evaluating Usability Methods: Why the Current Literature Fails the Practitioner,”. (You have to pay to read it online, unfortunately.) Dennis is annoyed with the current debate within the usability field about “how many users?” This debate recurs every professional generation, and, as he points out, generates a lot of heat with little light.
(The debate has lately been stirred up by Jared Spool’s group, with “Eight Is Not Enough”.)
Dennis, in a remarkably exacting fashion, demonstrates how this debate is pointless, because it assumes (among other things) that the single most important criterion of usability testing is finding the greatest number of problems. He reminds us that our practices derive from engineering, not scientific method. And as such, making smart trade-offs is essential.
From the essay:
[The criterion] is short sighted in that it ignores that problems should be fixed and not just found. If we considered instead a more relevant criterion—namely, how much can we improve the product in the shortest time with the least effort?—we probably would not have asked this question, or we would have asked it in a different form, such as, “What is the best way of deploying the usability resources we have available for this development cycle in order to maximize our beneficial impact on the product?”
Dennis works with Microsoft’s Game Testing User Research, which has published a number of articles that are freely available (if, annoying, in Word .doc format).
Abstract: http://doi.acm.org/10.1145/838830.838870
Spool’s so-called research is neither valid nor reliable. It’s just promotional material for himself and his company directed at the gullible.
I haven’t seen Wixon’s paper yet, but it sounds similar to, but less technical than, the classic, “Damaged Merchandise”: http://www.hfac.gmu.edu/~gray/pubs/papers/Gray&Salzman98_HCI.html
Of course Spool’s research is intended to drive business. And yes they focus a great deal of effort on bedunking myths. At the same time much of what they reveal is commom sense. Eight is not enough for a huge complex ecommerce site with lots of usability problems is not an unreasonable case to make. It’s ALL relative. There IS no one answer. Perhaps this is the point Wixon is trying to make.
If you choose to be a dupe to Spool, so be it.
Still don’t have Wixon’s paper, so a few comments on “What is the best way of deploying the usability resources we have available for this development cycle in order to maximize our beneficial impact on the product?”
Finding usability problems accomplishes nothing if they are not fixed. The gains from fixing usability problems must outweigh the costs. Choosing which problems to fix based only on the time and effort required to fix them does not maximize benefit. The choice must also take into account the resultant benefit of each fix (which relates to the severity of the problem).
For an interesting read related to finding problems (via heuristic review) and choosing which to fix, see Heather McQuaid and David Bishop’s An Integrated Method for Evaluating Interfaces.
I just read this quote today and I think it’s awesome:
It is by universal misunderstanding that all agree. For if, by ill luck, people understood each other, they would never agree.
Charles Baudelaire
Just thought I’d share.
Mike
I just read this quote today and I think it’s awesome:
It is by universal misunderstanding that all agree. For if, by ill luck, people understood each other, they would never agree.
Charles Baudelaire
Just thought I’d share.
Mike
I just read this quote today and I think it’s awesome:
It is by universal misunderstanding that all agree. For if, by ill luck, people understood each other, they would never agree.
Charles Baudelaire
Just thought I’d share.
Mike