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Interaction design is used to create useful, usable, and desirable software products for its users. However, there are groups of people who interact daily with software products but do not benefit from interaction design: software developers. These are the people that build our software, yet the tools they use are woefully inadequate.
expected change patterns and the software developer performing the changes. When change requirements exceed the skills or expertise of the software developer, three symptoms can be observed:
1. A change requires gathering of know-how.
2. A change is performed at many locations.
3. A change consists of values that depend on one another.
Conventions have an explosive nature. As software grows, more and more conventions overlap with each other. Consequently, the combinatorial interaction among them grows exponentially.
The existence of these conventions can point toward a definition of “good software design”— the state of software when developers can perform anticipated changes without proliferation of conventions.
Software development suffers from longitudinal usability issues. Software development tools (commonly known as IDEs, or integrated development environments) ask developers to continuously make small and seemingly unimportant decisions, which have subtle, long-term, and often large consequences. Without paying attention to “good software design,” maturing software becomes increasingly inert. Software design, however, cannot be qualified as good or bad in isolation. It is dependent on two external factors: the
What is common to all these symptoms is that they involve “conventions.” A convention consists of implicit rules, which are required to perform a change. The existence of conventions indicates considerable usability issues.
Conventions are physically separated from the software. In the best case they appear as comments or in separate documentation. But usually, they reside in the mind of the software developer, subject to being forgotten.
Conventions increase cognitive load for the software developer.
Owing to the nature of conventions, the software developer has to apply them repeatedly. Manual repetition provokes errors, which need correction. Consciously followed or not, conventions certainly create cognitive load.
When software is changed with a focus on supporting a particular functionality, the holistic design of the software gets out of balance—the conventions proliferate or become unknown. Changes to individual pieces of software, therefore, need to actively anticipate the future of “the whole” through a process of refactoring. Refactoring is the process of increasing software flexibility while user visible functionality is preserved. At
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