Department of Labor Logo United States Department of Labor
Dot gov

The .gov means it's official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Injuries, Illnesses, and Fatalities

Survey of Occupational Injuries and Illnesses Data Quality Research

In 2009, the Bureau of Labor Statistics (BLS) initiated research to assess the accuracy and overall quality of the data collected by the Survey of Occupational Injuries and Illnesses (SOII). This investigation was in response to critiques from outside BLS that the SOII was not producing accurate estimates of occupational injuries and illnesses.

Over the near-decade long investigation that has followed, many important insights into the SOII data quality have emerged. BLS is using these insights to take definitive action towards addressing the public’s concerns about SOII data quality. This page presents some important highlights of the research undertaken and the ensuing conclusions.

For questions, please contact us at or (202) 691-6170.

Q&A Overview

  • Are SOII data an accurate measure of nonfatal occupational injuries and illnesses?

    BLS and its research partners have conducted multiple studies which indicate that SOII fails to capture some cases, but could not determine the leading cause of an undercount. The estimated magnitude of the undercount varies dramatically based on various factors, including the case matching methodologies employed by the researchers.

  • What might impact the quality of SOII data?

    Employer interview results point to confusion among some respondents about various recordkeeping rules that could result in injury and illness cases going unreported to BLS or the specific details about a case being erroneously recorded and reported. A report by the Government Accountability Office also found numerous disincentives for both employers and employees to report a workplace injury. As an annual survey, the SOII may also fail to capture injuries or illnesses with a long onset or latency period.

  • What steps are being taken to improve SOII data?

    BLS has investigated the feasibility of multiple options for improving SOII data quality. These have included a multi-source approach, similar to CFOI, use of hospital data, workers compensation claims, and other sources. Based on results from a Westat and NORC analysis, BLS has developed and is currently piloting a Household Survey of Occupational Injuries and Illnesses (HSOII) for 2017-2018. It is hoped that this survey will complement the current SOII and resolve some of the issues surrounding quality.

  • What strengths does the SOII provide as an indicator of workplace safety?

    The survey is an important indicator of occupational safety and health. It is the only source of national-level data on nonfatal injuries and illnesses that spans the private sector and state and local government. The data are timely and have been collected since 1972. In addition to estimates by industry, the SOII publishes detailed case and worker information on a subset of cases.

Summary Timeline of Selected Research

Early critiques
(mid 2000s-2008)

Case matching

Employer interviews

Worker survey


  • News media articles and outside academic articles raised awareness of potential undercount
  • GAO report and Congressional hearings in 2007-2008 investigated possibility of undercount and funded ongoing research



  • Four states conducted quantitative employer interviews to understand recordkeeping practices
  • National follow-back survey of 2013 SOII respondents
  • Washington state interviewed a small sample apparently SOII-eligible workers' comp claims that were not reported


  • Westat conducted initial research into feasible designs for a worker survey pilot
  • NORC continued worker survey research and developed a survey instrument
  • BLS partnered with ICF to pilot a household survey (HSOII) in 2017-2018


  • BLS examined evidence of a possible SOII undercount


  • SOII was not capturing all injuries and illnesses within its scope, estimated magnitude varied by state
  • Washington state found that around 70 percent of SOII eligible workers' comp claims were captured in SOII
  • Multisource enumeration of workplace injuries and illnesses not feasible at a national level


  • Employers reported a variety of reasons for not reporting injuries and illnesses
  • Employer confusion over recordkeeping rules may lead to injury and illness underreporting and incorrect reporting of case type


  • Initial findings from a large pilot indicate it is possible to collect data on injuries and illnesses from workers, but not at the same level of detail and accuracy as from establishments


  • Congress funded BLS for an ongoing undercount research program in 2009


  • BLS turned to employer interviews to shed light on injury and illness recordkeeping practices


  • BLS began exploring feasibility of worker survey


  • BLS is testing approaches to improve the quality of injury characteristics collected from household respondents

Selected articles and publications

For a full list of publications relating to the SOII completeness research see here.


Last Modified Date: December 8, 2020