How to Improve Exposure Judgments

Last month I drew your attention to problems that can arise when we rely solely on our professional judgment to characterize exposures without adequate structure and tools. This month, I’ll discuss some of the reasons why professional judgments are so often inaccurate and offer suggestions for improvement. The discussion draws on A Strategy for Assessing and Managing Occupational Exposures, chapter 6, written by Susan Arnold, Mark Stenzel, and Gurumurthy Ramachandran, each of whom has contributed to influential research on the accuracy of professional judgment among industrial hygienists. THE PROBLEM To recap, a growing body of research indicates that our judgments are often wrong and tend to underestimate exposures, with potentially dire consequences for the workers we are hired to protect. Nor does experience insulate us from this tendency: some studies have found that OEHS experts’ exposure judgments can be worse than novices’ and not much better than judgments based on random chance.

The chart below illustrates this finding. The authors tested the ability of OEHS professionals to accurately determine in which exposure control category, or ECC, the 95th percentile of an exposure distribution is most likely to be found. As explained in A Strategy for Assessing and Managing Occupational Exposures, ECC 1 corresponds to a 95th percentile that is less than 10 percent of the OEL, ECC 2 to 10–50 percent of the OEL, and ECC 3 to 50–100 percent of the OEL. Exposures in which the 95th percentile is greater than the OEL are assigned to ECC 4.

The chart depicts the accuracy of novice and experienced OEHS professionals before and after training on using a checklist tool intended to provide structure to their exposure judgments. Prior to training, novices outperformed experienced professionals, and experienced professionals weren’t significantly more accurate than assigning an ECC randomly. Accuracy increased dramatically post-training for both novices and experienced professionals.

FAST THINKING VS. SLOW THINKING Why are our exposure judgments so often inaccurate? The answer may lie in the way our brains process information.

Regular readers of The Synergist will be familiar with the ideas of the psychologist Daniel Kahneman, whose 2011 book Thinking, Fast and Slow has been referenced in several articles over the last few years. Kahneman’s insights about subjective judgment, which he defines as “nothing more and nothing less than recognition,” include the observation that “intuition can be a useful tool aiding in accurate decision making if, and only if, it is followed by the disciplined collection of objective information with disciplined scoring and analysis of that information.” Subjective judgment occurs in the part of the brain known as the pre-frontal cortex, which is prone to distractions and biases that we may not perceive. As a result, our subjective judgments are inconsistent at best.

The “fast thinking” of Kahneman’s title is akin to a gut reaction—an automatic, impulsive, and subconscious response to a situation or event. “Slow thinking,” by contrast, is deliberate, analytical, and conscious. A central issue with subjective judgment is that it often relies on fast thinking when it would be far better served by slow thinking.