Epidemiology-Based Ergonomic Analysis for Data Driven Decisions

Epidemiology is the study of factors that determine the occurrence and distribution of disease in a population. In epidemiology, risk is defined as the proportion of people who are unaffected at the beginning of a study period, but who experience a risk event during the study period. The odds ratio compares the odds of having the condition if the risk factor is present with the odds of having the condition if the risk factor is absent. Although many epidemiology research studies have provided odd ratios and have been available for more than thirty years, no analysis methodologies have utilized odd ratios to quantify ergonomic risks associated with the development of musculoskeletal disorders. Carpal tunnel syndrome, low back pain, and rotator cuff injuries occur in the general population at a given rate. These injuries are not unique to manufacturing or material handling job tasks. Additionally, there are nonoccupational risk factors with associated odd ratios that allow us to now determine the predominant cause of an injury. The odds ratio compares the odds of having the condition if the risk factor is present with the odds of having the condition if the risk factor is absent. Displaying results in terms of odd ratios allows the end user to understand the odds of a musculoskeletal injury in terms of the risk above the general population. Unlike many traditional ergonomic assessments that use fixed scales and arbitrary red, yellow, and green zones, odd ratios have no end limit. Therefore, as risk factors increase, increased risk is reflected as a higher odd ratio.