Thursday, December 28, 2006

Tradeoff between safety and speed

I saw a great example of how workers sacrifice their safety to save time. Why do they do this when their safety is their own, whereas their labor profits their company? It is not a pure economic decision. In general, it is just the assumption that the loss in safety is not very big (even though they are often wrong about this) and saving time is a natural human objective, even when there is little direct benefit. And there may be some benefits in terms of making the boss happy and getting good evaluations.

So here is the example that I saw: lets call it the ladder wiggle. A contractor was near the top of a 15 foot ladder leaning onto the roof of a one-story storefront. He needed to move the ladder about a foot forward to reach what he was working on. It would have taken maybe 30 seconds to climb down the ladder, move it, and then climb back up. But instead, he grabbed onto the edge of the roof to support some of his body weight, and wiggled the ladder side to side and shuffled it forward. Watching this with some fascination, I estimated about a 10% chance that the ladder (and the worker) would fall. 10% is not bad, but is it worth saving 30 seconds? Apparently, it was to him.

The cognitive process is simple. There he was on the ladder and the most direct way to move it was the ladder wiggle. Rather than a cost/benefit analysis, which would have resulted in a safer solution, he evaluated his first option, determined the risk was acceptable, and did it. As with RPD decisions, it was not a comparison of alternatives.