In the past ten years, processing plants have been adding computer-based decision aids to their process control systems. These systems monitor process parameters and send operators messages on actions that need to be taken. The concept sounds like a good idea; the computer can aid the operatorís thought processes, which should reduce the chances of error. Unfortunately, new research indicates the decision aids can have the opposite effect and increase operational error.
In one recent study, researchers from NASA, the University of Illinois, and San Francisco State University used a basic flight simulator to study 80 student volunteers carrying out flight tasks. First, volunteers were trained to use the simulator. Then each had to fly eight "missions" involving a total of 100 tasks, such as pressing buttons when they passed beacons or when gauge levels dropped. Half the students were given automated cues which they were told would be almost perfect, though not infallible, to remind them to carry out the tasks. Over the trials, the machine gave a false cue six times and failed to notify them of six other events. The other volunteers just used instrument readings on the simulator's display, which both groups had been told would be 100% accurate.
Volunteers using automated cues on average carried out only 59% of the tasks that the computer hadn't prompted them to do. But those who relied on the instrument readings were 97% accurate in performing these tasks. The computer-prompted volunteers also carried out 65% of the wrongly prompted tasks, despite contradictory instrument readings. In short, the computer prompts actually made people more prone to errors.
The study raises some serious issues with adding decision aids to process control systems. Tech managers wonder where their automation dollars should be spent. In light of the current study, managers would be far wiser to spend their money improving the human factors of their existing alarm and display systems rather than adding a costly new layer of automation that can actually degrade performance.
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