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By Anthony Andre, PhD.
Interface Analysis

In a recent usability study conducted by Interface Analysis Associates, 24 intermediate to highly experienced computer users were observed while they were attempting to perform basic tasks in common software applications. Their interactions with the software were analyzed in terms of length of time, number of mouse clicks, and successful completion of the tasks and when compared to optimal performance standards. The results showed that, on average, participants either took longer and used more mouse clicks than necessary to successfully perform common computer tasks, or they couldn’t figure out how to complete a task. In the end, the study suggests that for every 8 hours of computer work, the same work could have been performed in only 40 minutes if the software training had been provided!

Impacts on You
During these periods of inefficiency, participants were observed for body postures and other behaviors, such as facial expressions (indicators of frustration or stress) and verbal utterances. These observations revealed the impact of software inefficiency in four main areas:

Time: The more inefficient we are as computer users, the more time we spend sitting in front of the computer. The negative effects of prolonged sitting include poor circulation; muscle fatigue; back, shoulder, and neck pain; eye strain; and more.

Repetitions: Inefficiency results in more mouse clicks and keystrokes, that is, higher repetitions.

Posture: Our postures change when we can’t easily accomplish our goals with our computer software. For example, we lean forward, we hold the mouse with our arm outstretched and shoulder raised, and ultimately we lose the basis for the support of good body posture.

Stress: With each failed attempt to carry out a specific action or command with our computer software, we experience higher levels of stress, frustration, and time pressure.

Conclusions and Guidelines
Computer users are encouraged to explore ways to improve their computer interaction efficiency and seek training in the software programs and operating systems they use in their workplaces. Indeed, most of the participants indicated that their interactions with software would be more efficient with formal training.

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Department of Industrial Relations   Cal/OSHA Consultation Service   Research and Education Unit