Bad design practices – Generalizing

By Lynn Miller

In my previous blog post I covered some of the factors that contribute to overdesign. There is one factor I would like to talk about in more detail: Overgeneralizing the problem.

Let’s say you own an old building that has been converted into apartments. During the renovations all of doors were modified to be a standard door height or higher, except one. One door at the back couldn’t be changed and is lower than the rest. People keep hitting their heads on this door and you would like that to stop as the liability insurance is getting expensive.

You bring in two designers who walk around the building observing everything, and who witness people bonking their noggins on the offending door. They go off and design their solutions.

Designer 1 comes back with a paper sign that she plans to affix to the top of the door. Then she will observe to see if it works and tweak wording and placement as necessary.

 

 

Designer 2 notes that one really tall guy needed to duck at all the doors, not just the low door, and that shorter people didn’t have a problem with the low door. So his solution is to put a sign beside every door that says what the clearance is (5’ 6”, 7’ 0”, 7’ 4”) so that the user can decide if they need to duck or not. This solution, he argues, works for all cases and makes the door signage consistent. He is so confident that he doesn’t think that testing is necessary and suggests you get 372 of these signs made right away in a nice walnut with copper trim.  He has even mocked up an example of what the sign should look like:

 

 

Designer 2 has overdesigned by assuming that a specific issue extends to a wider range of cases – in other words, by making the problem bigger than what has been observed. He has given equal weight in the design to the edge cases (very short or very tall people) even though there was no observed problem for them. If he didn’t actually see people having a problem at the other doors and has simply assumed there is one because of overgeneralization, then he is designing a complex solution when one is not required.  Not only is his design much more costly to implement, but because it is complex and doesn’t address the root issue (a low non-standard door takes people off guard) then it is not likely to even work.

There are many other issues with his design. Can you spot them all?

Comments

[Karthur]

But aren't you dismissing the possibility that humans will evolve to all be really tall or really short and thus we should design for that? And could you please do a study to tell us how tall our users are? We have no idea. :)

Good post. I'm very familiar with this problem, though in my case I see it coming more from engineering stakeholders than from designers.