ION - Waterloo Region's Light Rail Transit

[danbrotherston]

And I do really think that usage errors are always the fault of design (within the "in context" caveat I described at the beginning). It is the job of a designer to build a system which is easy to use.  That is not to say that there aren't other tradeoffs in design, absolutes are rarely useful, and extremely infrequent errors may not be worth the effort of overcoming, but it is a principle of design that systems should be easy to use, errors should be hard to make and failing that easy an intuitive to recover from. I do highly recommend the book by Don Norman: http://www.nixdell.com/classes/HCI-and-D...dition.pdf

I think we basically actually agree, it’s just a matter of emphasis and wording.

For the record I agree that the design of a fare tap machine needs to be adjusted until substantially all the people who encounter it have little to no trouble using it the first time, and no trouble on subsequent times. If this requirement isn’t met, there is a problem, possibly a subtle one, with the affordance offered by the device.

I just don’t think it’s appropriate to “always” blame the design. But it’s not clear to me that even you think that, since in the same sentence that you say “usage errors are always the fault of design” you immediately add a parenthetical about context, and then later in the paragraph you refer to tradeoffs.

I’m sensitive to this issue because I’ve seen concerns about people having trouble using something spiral out of control. Way back I was a lab instructor for a computer science course with an absolutely enormous series of lab exercises. As far as I could tell, the reason the exercises were so enormous was because every time a student had any sort of confusion at all, a sentence or paragraph was added to try to head that off. The result was an unreasonably large document whose size was the biggest barrier to convenient use. They would have been much better leaving out most of the detailed explanations and just accepting that the lab instructors would sometimes need to answer questions from students (which was the case anyway, because people couldn’t find the information they needed in the oversized document). In other areas, I’ve seen systems lose features that are important for advanced use because of fears that people new to the system would be confused by the extra features. But it’s not reasonable to be confused by the presence of a single button labelled “Advanced…”.

Returning to the issue of the transit terminal, let’s hope they adjust the design so that it works better for riders. Although I guess all we can really expect at this point is signage, which isn’t the ideal way of resolving issues of this nature.

The point about context is that it matters who your users are. Again, if I get in an airplane, and cannot fly it, it's not a design failure because, I, a lay person with no flight training, is not the intended user of an airplane. Where as a transit system is designed to be used by everyone.

As for tradeoffs, the fact that user error is the fault of design does not mean that the designer was wrong to make those design decisions, there are always competing factors, but it is still the design causing that confusion.

For your example, what you are describing is still bad design. A document which is too large and doesn't provide clear focus and organization is also not designed well for the intended users, and as you explain, causes it's own problems.

Design is not simple, there are tradeoffs (length vs. clarity), but that does not mean there aren't better designs, (for example, shorter lessons with an appendix might be solve both problems) and there are questions about the whole system, e.g., the lab book is only part of the whole learning experience, perhaps the software you are teaching about could have it's user interface improved, but now you have trade offs between learning and using.  And of course, it doesn't end there, if there are errors that are going to come up, those errors should be helpful and instructive.

But someone who says "users just need to learn to tap right" is pretty clearly wrong, if users are having problems with tapping, the design of the terminal is faulty, just as if users are having trouble using a door, the design of the door is faulty, they're both very basic very simple tasks. Far far too often in pretty much all of life we blame the user instead of the designer. That's why Norman's book is so good, he talks about so many examples where the user is blamed instead instead of the design, it really is enlightening.

Like you say, we probably mostly agree, it's only a question of frequency. I'd say 97 times out of 100, design is at fault for common errors and user confusion, 2 times out of a 100 it's a system which is being used by someone who legitimately not the intended user (not just a user the designer failed to remember), and the last time 1 out of 100, it's a system which has made reasonable tradeoffs and has accepted user error and confusion as a feature of using the system.  But that's just my off the cuff opinion.