That Technology Magazine

There is this thing that one could describe as “usability on auto-pilot” (or “usability out of control”). This is when usability guidelines and heuristics are used simply for their own sake. Design decisions are then based on the “automated” application of guidelines without evaluating their appropriateness or the need for adapting them to the context of the system under investigation.
One good example is “consistency”. Consistency is one of the guidelines you’ll encounter in usability checklists (for all purposes). But when it comes to making an interface “consistent”, things often become difficult…or funny, as in the following example.

The task was specifying the keyboard navigation for a user interface, including the tabbing order, i.e. determining in which sequence controls and fields get the focus when the user keeps pressing the TAB key.
The interface contains several forms that are used to determine the attribute values for different objects via entry fields. Each object has several attributes with a considerable amount of overlap between different objects’ attributes. For example: there is object 1 with the attributes A, B, C, D, E, object 2 with the attributes A, B, D, F and object 3 with the attributes B, C, E, G.
The crucial aspect is that the importance of attributes varies for different objects, e.g., attribute A was of major importance for object 1 while it was of minor importance for object 2, i.e. entering a value for attribute A was not always required for object 2.
So far, so good.
Now a suggestion was made, to have the forms “consistent”, i.e. having the form layout for the individual objects as similar as possible by placing fields for identical attributes at identical positions for the individual object forms. At the same time, a requirement was to support the user by “tabbing through” the fields according to their importance, starting with the focus on the most important one. The combination of suggestion and requirement led to tabbing orders like the one shown on the image.

Needless to see that such a tabbing order would be…surprising…for the user, who could never anticipate where the focus would jump next.
The solution was, of course, to “skip” consistency on this one and layout the forms “inconsistent” but in a way that supports data entry in an optimal way (and ending up with a tabbing order left to right, top to bottom).
As stated in this post on the Three-Click Rule, sometimes clients need to be educated about the fact that guidelines are no laws and that breaking them may sometimes be justified.