Resource efficiency

NYC blackout. On July 13, 1977, a lightning strike tripped two circuit breakers. Another strike caused the loss of two transmission lines, resulting in the overloading of several power plants. An hour later the Con Edison operator tried and failed to manually shed load. Ten minutes later the Con Edison power system shut down. (http://en.wikipedia.org/wiki/New_York_City_Blackout_of_1977). The interaction fault was due to a usability mismatch, in which the operator turned a control knob to the wrong direction (Casey, 1998 – An Act of God).

A simple usability test at the prototype stage could have revealed the potential operator's difficulties. A redesign of the GUI, implementing usability guidelines and scenario-based information visualization, based on operator task analysis, could have enabled the design of a new GUI, which ensured that the operator would set all the parameters relevant for the scenario, thereby shortening the pre-production verification cycles.

Engine overheat. This interaction fault is well known to most car owners; it is of engine overheating due to lack of coolant fluid. The problem is that the gauge of the engine temperature indicates that the temperature is too high only after it is too late. Many car engines suffer daily from severe damages due to this problem.

A review of the usability aspects in the system failure analysis could make a point about the unreliability of the failure indication, and its potential consequences.

This last example demonstrates that global economical interests might sometimes contradict those of the system providers, which suggests that governments should be involved in developing and enforcing usability standards.