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Handbook of Methods Survey of Occupational Injuries and Illnesses Data sources

Survey of Occupational Injuries and Illnesses: Data sources

Although SOII began as a mail-based survey, most of the SOII data are now collected electronically. Data collection methods for SOII have evolved significantly in recent years in response to BLS goals to collect data more efficiently and to provide more timely and accurate data to its users. Expanded use of available technologies—namely the Internet and other electronic resources as alternative means for responding to SOII—has reduced data collection and processing times. The result has been more timely publication of SOII estimates.

Establishments selected to participate in SOII are notified by BLS in writing in advance of the year for which they will be required to provide data. This notification process ensures that even those establishments not normally required by OSHA to maintain injury and illness logs and case forms will do so for the survey year. Employers then receive instructions on how to record and report their injury and illness experience from state agencies, or the BLS itself in nonparticipating states, early in the year following the year which they are required to record. These packets arrive via mail, but the instructions recommend electronic submission.

Employers have the following options available to meet their requirement to respond to SOII:

  • Internet. The Internet Data Collection Facility (IDCF) is a centralized platform used by SOII and other BLS programs. The IDCF provides a uniform, manageable, and secure environment for BLS survey collection via the Internet. BLS first used the IDCF for the 2002 survey year. The IDCF survey instrument is a Web-based tool that provides sampled employers the ability to respond to SOII online. Employers can enter their injury and illness data, along with employment and hours worked, using an Internet-based system that is designed to resemble as closely as possible the hard copy survey forms that employers traditionally received and responded to by mail. Approximately 73 percent of responses to the 2014 SOII were submitted via the IDCF.
  • Fax form. Employers may request a standardized fax form that they can complete and fax back to BLS.
  • Telephone. Employers may call a SOII representative and report their data over the phone.
  • Mail. Employers may elect to receive and report their data using a hard-copy, paper survey form that is mailed to them and returned via mail to BLS.

Survey responses received by mail, fax, or telephone are manually keyed into the SOII data collection system.  Internet responses remove this manual processing because data are entered directly by the employer in the IDCF and then uploaded into the SOII data collection system. Therefore, Internet responses reduce processing time and remove the risk of errors associated with the manual keying of data required of SOII responses received in hard copy format (e.g., mail or fax). Electronic reporting options may also include in-line edits that assist respondents or immediately identify erroneous data that can be corrected by respondents before submitting their data. All responses, regardless of which reporting option was used, are electronically edited. Responses that do not meet the computer screening criteria or pass senior staff review are subsequently verified with the employer.

Regardless of which option an employer chooses for responding to SOII, each form has been designed to resemble employer OSHA recordkeeping forms to allow for easy transcription.

The SOII data collection form is organized into distinct sections, as follows:

  • Section 1: Establishment information
    This section asks employers to provide basic information about their establishment, including the number of employee hours worked (needed in the calculation of incidence rates) and the reporting unit’s average annual employment.
  • Section 2: Summary of work-related injuries and illnesses
    This section asks employers to summarize the number of injuries and illnesses incurred by employees at their establishment, as well as the type of injury and illness cases that occurred. These data can be copied directly from employer injury and illness logs.
  • Section 3: Reporting cases
    This section asks employers to provide detailed information on the worker and the circumstances of the injury or illness for cases that resulted in at least 1 day away from work or, for cases that resulted in job transfer or restriction for selected industries participating in the days of job transfer or restriction (DJTR) pilot study. These worker and case details can be copied from the employer’s OSHA case forms. State agency and BLS personnel review the summary data (section 2) and codify the details for the cases reported in this section (see discussion of OIICS in the concepts section) of serious cases (section 3), verifying and correcting apparent inconsistencies by contacting the employer again.
  • Section 4: Contact information
    This section asks employers to provide contact information for the individual who completed the survey form in case there are discrepancies in the reported data that require correction.
  • Section 5: If you need help …
    This section provides employers with contact phone numbers within each state should they have questions or require assistance in completing the survey form.

Every year, by midsummer, the active data collection phase of SOII is completed and the preparation of data for both national and state estimates of nonfatal occupational injuries and illnesses begins. Estimates of the incidence rates and counts of employer-reported injuries and illnesses by detailed industry and type of case are published in late-October. A subsequent release in November provides estimates on the details of the case circumstances and worker characteristics for injuries and illnesses that involved days away from work.

Mining data are collected by the Mine Safety and Health Administration (MSHA), and railroad data are collected by the Federal Railroad Administration (FRA), which are then provided to SOII for inclusion in the estimates.


All data collected in the SOII are subject to the BLS confidentiality requirements that prevent the disclosure of identifying information. Data collected from SOII are used solely for statistical purposes. All BLS employees and the state grant agency partners who work with the SOII data take an oath of confidentiality and are subject to fines and imprisonment for improperly disclosing information provided by respondents. Confidentiality certification training is required annually.

At BLS, the data are processed and stored on secure servers, with access limited to employees having security clearances.

Last Modified Date: October 30, 2020