Ten Principles of Good Design Redux | Part 4
This principle is applicable in two areas; firstly to User Interface Design and User Experience Design, and secondly to the Conceptual, Logical and Physical Designs of a software system. In the case of the latter the comprehensibility of a software system design is so obviously vital to the successful realisation of that design that I will focus this post entirely on the former.
The ease with which a user comes to understand the visual metaphors utilized in a user interface, and thus the speed with which they can accomplish necessary tasks and operations, defines how usable that user interface is. From a user experience perspective “understandable” and “usable” are synonymous.
In 1995 I worked for a progressive IT company who were in the process of setting up a full usability testing lab. The plan for this lab called for the installation of cameras for recording video of the user’s facial and body language, a key and mouse logger to monitor and capture user input data, a pulse monitor to measure the user’s stress levels, and a high resolution screen-capture of the user’s interaction with the application itself. The plan even called for having statisticians and clinical psychologists on staff to structure the usability tests and interpret the integrated data streams. The goal was to not only test the usability of clients applications, but also gain a deep understanding of the Laws of Usability. I left the company before the plan was realized, to go and work on a new shiny thingy called the “World Wide Web”, so unfortunately I never got to see the lab completed, but it did introduce me to Usability as a sub-domain of Software Design. Even in 1995 the importance of Software Usability and Interaction Design, and their significant impact on the successful development and adoption of software, was well understood, though the Laws themselves had not yet fully emerged.
In the mid 2000s, while at Microsoft, I was fortunate enough to interact with some of the brilliant User Experience folks in the Windows Product Group and Microsoft Research. They were on the very bleeding edge of User Interface and Experience Design. Despite all of the UI innovation that happens in these teams, Microsoft has to be conservative in its adoption of these UI innovations because of the very broad use of their client operating systems; I saw many mind-blowing UI prototypes during that time, and I have seen a small percentage of the elements of those prototypes show up in shipping Microsoft products. Working with these teams gave me some idea of just how far the User Experience Design discipline had come in a relatively short time; Usability had gone from being a Craft to a fully-fledged Science, with its own sub-disciplines, laws and formalisms.
The Web has had a massive impact on our understanding of what makes a user interface usable and understandable. Because of their rapid mutation and evolution in response to users explicit and tacit feedback, web pages are to Usability Engineers what fruit flies are to Geneticists. User interface and experience design on the web has been highly experimental because of the breadth of its accessibility and the relative simplicity of web technologies. It has brought about a “democratization of [UI] design”. I am continually amazed at the brilliant UI that I see online.
A couple of years back I read a great book that further formalised the way I approach User Interface design. It is called “Super Crunchers: Why Thinking-by-Numbers Is the New Way to Be Smart” . It obviously is not a UI Design book; It is actually about the hidden knowledge in the Exabytes of digital data that we generate, which can be revealed by applying various statistical analysis techniques. There is a great chapter about the use of randomized testing to improve the usability of web sites. The study documented in the book suggests that there are in fact no Laws of Usability, and that there is no such a thing as a user interface that will be usable and comprehensible by all users. It further suggests that the key to a usable interface is adaptability and customizability.
Ideally a user interface should adapt or be adaptable to each individual user. A user should not have to learn new visual and interaction metaphors to get a task done. “Fortunately”, the software industry has forced users to learn a lot of metaphors, e.g The Desktop, The Hyperlink, The Tree View, etc., which can now be used relatively freely, though we should certainly not feel obliged to use them. If possible a user interface should simply adapt without requiring that the user explicitly set a number of configuration options. At a minimum a user interface should give the user a simple mechanism for customizing the user interface to suit their preferences or preferred interaction “style”.
An example of an excellent user interface is Microsoft’s Visual Studio 2010. For a product with so many features and capabilities, I find it incredibly easy to use and fully configure to my personal preferences. Obviously this is not a general purpose product, but for those who use it, i.e. software geeks, it is easy to understand and is highly usable (except for the occasional performance issue). I have used Eclipse in anger (pun entirely intended) over the course of the last decade and it offers a good Usability counterpoint to Visual Studio 2010.
So one would image, given what we already know about designing easily understood and usable user interfaces and experiences, that all modern user interfaces would be highly usable. Sadly that is not the case; I still see product after product, solution after solution, and web site after web site, designed so poorly that only a Visual Basic programmer from 1993 could love them! There really isn’t any excuse.