June 2014

Examining the completeness of occupational injury and illness data: an update on current research


BLS used the new funding to sponsor research in three areas:

  • Matching additional SOII and workers’ compensation data, building on prior studies
  • Matching multiple data sources for two specific natures of injury or illness—work-related amputations and carpal tunnel syndrome
  • Interviewing employers about their practices for identifying and recording cases on OSHA logs and workers’ compensation claims

BLS staff, several state agencies, and one university researcher conducted this initial round of research over 3 years, with final results completed in summer 2012. At that time, BLS convened all those involved in the research as well as non-BLS stakeholders to hear presentations on research results and to develop consensus recommendations for moving forward. Each research topic is discussed below, with a focus on the Bureau’s interpretation of the results and impact on the program. These summaries are followed by a look at future activities.

This article updates an August 2008 Monthly Labor Review article, “Examining evidence on whether BLS undercounts workplace injuries and illnesses,” by John Ruser.8 The earlier work provides considerable detail about the BLS survey and the early matching studies that led to concerns that the SOII undercounts workplace injuries and illnesses. Many of those details are not repeated here, except where needed to provide context for new findings.

Understanding the “undercount”

The first two research projects, which involve the matching of data from different sources, are intended to identify a broader universe of injuries and then determine which of these injuries should be reported to SOII. In the case of the SOII-workers’ compensation match, comparable cases are those which meet OSHA recordability definitions and extend beyond any workers’ compensation waiting period.

The multisource matching project goes beyond OSHA-recordable (and SOII-eligible) cases to identify a complete count of all nonfatal occupational injuries and illnesses, including cases that are not OSHA recordable. This broader measure is of interest to public health professionals seeking to identify interventions and safety protocols related to the total burden imposed by workplace injuries and illnesses, including injuries and illnesses to workers who are not currently included in the SOII—such as federal government employees9—and those to self-employed individuals (the self-employed are not identified in SOII because it is a survey of employers). Further, this broader interest includes cases that may not meet OSHA definitions and may not exist in the OSHA records used in the SOII, such as long-latency illnesses.

The SOII sets out to estimate OSHA-recordable injuries and illnesses occurring within a given year, as identified by employers. While there may be an undercount of such cases, this more narrow scope is still vitally important to public health officials and others. It may be possible for SOII data to be used as one input as the public health community attempts to identify the various components of the total burden of workplace injuries and illnesses, but complete data on such burden will have to come from a variety of employer-based and nonemployer-based sources.

Matching SOII and workers’ compensation data

Concerns raised in the mid-2000s about the completeness of SOII data stem from projects that matched data on individual cases from the SOII with case data from individual state workers’ compensation systems. When the OSH Act authorized the Department of Labor to develop workplace injury and illness recordkeeping definitions and procedures, the result was the first consistent set of data across states and industries. Workers’ compensation, on the other hand, is a state program with state-to-state differences in definitions and procedures.10 Differences between the SOII and workers’ compensation systems had long been suspected, based on previous comparisons of aggregate counts and studies of selected industries or injuries.11 The mid-2000s studies were the first to match case data from the two systems: one researcher matched data for Michigan, and a second researcher matched data for six different states. The results suggested that the SOII and workers’ compensation systems each missed cases and that there were cases missed by both systems.


8 See Ruser, “Examining evidence.”

9 BLS added state and local government employees to the SOII in 2008. BLS is currently working with OSHA on plans to capture occupational injury and illness data for federal government employees. Although BLS plans to publish data for federal workers, a time frame for the inclusion of these additional data has not yet been determined.

10 A good source of information on workers’ compensation programs in the United States is the Workers’ Compensation: Benefits, Coverage, and Cost annual report produced by the National Academy of Social Insurance, available at

11 For a good discussion of prior studies, see Ruser, “Examining evidence.”

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About the Author

William J. Wiatrowski

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