The purpose is to design systems/software so that they are easy and effective to use even though their design is often based on efficacy and cost-effectiveness in the first place. Intolerance for bad design rises over time and avoidance takes place. Errors are also more likely to occur with poor interaction design and can have disastrous outcomes. Given the increasing interaction of computers systems within organisations and systems there is often the likelihood that poor interaction design causes wider problems than simply data error.
Operating system developers like Microsoft and Apple allow for predictable responses to user interface. This allows expected responses and more chance of successful outcomes. Apple even goes as far as publishing a user interface design guide for developers wanting to develop apple platform applications.
One standard for checking effective interface design is ‘program correctness’. The parameters for correctness depend mostly on what conditions of response to valid and faulty input. A fully correct program works correctly with all valid input and for all conditions of faulty input gives a reasonable answer.
Systems should be designed for their target audience. The mindset of many system designers is still to think of what is acceptable form thier level of knowledge concerning the system. Developers of successful systems have thought of what the level of knowledge of their audience is and catered their system and it’s user interface towards it. Ane example of this might be the appropriate use of internationalisation to correctly cater for different languages/cultures.
One of the techniques of successful interface design is to picture a collection of user personas to test against the interface/system. this is more useful than merely asking the question, “Does this interface suit the user”. By specifying many variable personas different inputs and interactions with the system are tested.
After reflection of how I have handled interface design in the past and how I might apply it in the future I recognise that one of the biggest pieves of the puzzle is not letting the ego take control of the process. It is easy to become invested in the design of a system to the point where one finds criticism irritating rather tan constructive. The answer to this lies perhaps in taking on a collaborative apporach with users of the system as early and as often as possible in the process of design. This may help prevent the ‘walls’ one might put up that may interfere with a truly user focussed interface.