Expenses, user interfaces – and Scott Adams

My first go at doing my expenses on the new system failed totally.  My claim was rejected for not having given home-to-office deductions, despite the fact that the question hadn’t been asked and on looking at the claim again, there didn’t seem to be any way of entering them in the first place.

By coincidence I had been reading Bruce Tognazzini’s latest column:

the designer develops a “Design Model” of the software, communicates it through the “System Image” – the look, feel, and behavior of the interface. The user, in turn, attempts to recreate the Design Model through experiencing the software. This understanding then forms the user’s assumptions, the filter through which they will interpret all further instructions.

If users only worked from the information contained in the System Image, they would likely create reasonably accurate User Models. They don’t. Rather, they intermingle their past experiences with information extracted from the System Image when building the User Model. When their past experiences fail to jibe with the system image, or when the system image is ambiguous, users are highly likely to misinterpret the designer’s intention.

The explanation turns out to be that in the old system, home to office was indeed a deduction from a claim which was itself primarily organised by date. In the new system, home to office isn’t a deduction in the same way at all – it’s a potentially negative expense line in its own right (further complicated for those of us for whom it is always zero – the concept of a mandatory zero negative claim raising some curious conceptual questions). In other words, there is an assumption that users will immediately change their user model in response to a change in the design model expressed through the system image.

They don’t, of course. And if the system designers had thought this through, their communications might have been very different.  On the whole the new system is pretty intuitive (where “intuitive” is not necessarily the opposite of “clunky”) – if they had stopped to think which were the bits that might create some cognitive dissonance, the transition could have been supported much more effectively.

The implications of all that for other areas don’t really need to be spelled out…