October 2013

Using workplace safety and health data for injury prevention

The broad array of data available from the Bureau of Labor Statistics on occupational safety and health may make it difficult to hone in on the root causes of workplace injuries and the strategies for preventing those injuries. This article uses descriptive statistics and trend analysis to develop a framework for enabling such investigations. The focus is on five factors—sequence of events, frequency of incidents, severity of injury, interaction of circumstances, and contributing factors—that, if taken into account as part of data analysis, may help data users uncover both root causes and effective preventive strategies.

Much is known about workplace injuries—their frequency, the manner in which they occurred, the resulting physical effects, and more. But how can employers, policymakers, and others best use these data for training and prevention purposes? Is it enough to know that 41 percent of all fatal work injuries in 2011 were the result of transportation incidents? What does the fact that nearly one in three nonfatal workplace injuries requiring days away from work in 2011 was a musculoskeletal disorder reveal about preventing such incidents? Do workplace injuries affect different groups of workers in different ways? These are just a few questions that might need to be considered in an effort to get to the root causes of workplace injuries.

“Root cause” is an abstract concept and one that is not perfectly defined. There is much literature in the business world about identifying the root causes of workplace problems (not just safety issues) and attacking those causes.1 The present discussion adopts a similar approach by identifying those factors that, if addressed through training and prevention techniques, can help reduce workplace injuries. Data from the Bureau of Labor Statistics (BLS) may hold some answers.

The BLS Occupational Safety and Health Statistics program consists of two sets of data: the Survey of Occupational Injuries and Illnesses (SOII) and the Census of Fatal Occupational Injuries (CFOI). The SOII provides estimates of the number and rate of nonfatal occupational injuries and illnesses by industry and state. It also captures additional detail on the workers involved in an incident and the incident’s circumstances for the most severe cases, including those that result in at least 1 day away from work, and, just recently, for a subset of cases resulting in job transfer or restricted work. The CFOI provides a complete count of fatal work injuries, with details about the workers and the incidents. Together, the SOII and the CFOI form a comprehensive U.S. workplace safety and health surveillance system.2

This article goes beyond descriptive statistics to explain some ways of using workplace safety and health data to identify the underlying causes of workplace injuries. The focus is on five approaches that may help illuminate the root cause of an injury:

·         Examining the sequence of events to understand what really happened

·         Considering the frequency of incidents

·         Assessing the severity of an injury

·         Looking at the interaction of circumstances surrounding an incident

·         Identifying contributing factors

In 1992, BLS introduced the Occupational Injury and Illness Classification System (OIICS), a classification system used to describe all fatal injuries and the most severe nonfatal injuries and illnesses. Beginning with data for 2011, this system was revised to incorporate new types of diseases, provide consistency with other disease and injury classification systems, and alter certain coding with the express intention of improving information available for injury prevention.3 In describing the various factors underlying workplace injuries, this article identifies changes to the OIICS and the resulting change in data.


1 Root cause analysis attempts to identify and correct the underlying reason for a problem, rather than simply the obvious symptoms. The following link is to one of many available commercial resources that provide more information on root cause analysis:

2 For complete information on, and data from, the BLS Occupational Safety and Health Statistics program, go to

3 The OIICS is available at For information on the recent changes to the OIICS, see Joyce M. Northwood, Eric F. Sygnatur, and Janice A. Windau, “Updated BLS Occupational Injury and Illness Classification System,” Monthly Labor Review, August 2012, pp. 19–28,

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About the Author

William J. Wiatrowski

William J. Wiatrowski is an economist in the Office of Compensation and Working Conditions, Bureau of Labor Statistics.