The Variability and Unreliability of Human Performance

Human variability can add to the sources of uncertainty in a dangerous and unpredictable environment. Davitt McAteer (1995) writes  

By definition, the working environment changes all the time. As mined material is removed, an entirely new workplace is created in as little as 24 hours. Roof conditions vary from place to place. 

Explosive methane may be liberated. Mechanical systems may fail. A mine that is safe one day may be dangerous the next. A mine with a good safety record may confront new challenges daily. Personnel changes, too, can make a dramatic difference in the. safety of a mine.  

When miners worked as apprentices, master miners could adjust their learning styles to the needs of their apprentices and the specific conditions. Young miners could learn a variety of methods by working closely with different miners. When British Coal introduced standardized training schemes, however, these new procedures could not take into account individual differences in knowledge and experience. One miner claimed that safety standards were created by safety managers who were totally separate from the safety culture at the mines. 

Miners like O Sullivan lament the loss of the old safety culture Fifty years ago, apprentice miners did all jobs of mining under the supervision of an experienced miner. You learned the conditions and how to respond New train- 

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This chapter provides a brief overview of the most important sources of rhetorical uncertainty in technical documentation in the workplace the dynamic uncertainty of hazardous environments the variability and unreliability of human performance the uncertainty of what one agency calls premium data uncertainty in social structures and organizations and the rhetorical incompleteness of any single viewpoint. As the examples in this chapter demonstrate, the material and institutional uncertainty of hazardous environments affects documentation practices at all levels. But documentation practices can also contribute to uncertainty, particularly when writers depend too heavily on agency conventions to structure recommendations and conclusions. 

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