"Occupational safety and health stakeholders we interviewed and occupational health practitioners we surveyed told us that primary factors affecting the accuracy of injury and illness data include disincentives that affect workers’ decisions to report work-related injuries and illnesses and employers’ decisions to record them. Stakeholders most often cited workers' fear of job loss and other disciplinary actions as disincentives that can affect workers' decisions to report injuries and illnesses. Occupational health practitioners concurred: 67 percent reported observing worker fear of disciplinary action for reporting an injury or illness, and 46 percent said that this fear of disciplinary action has at least a minor impact on the accuracy of employers' injury and illness records. Workers’ fear of disciplinary actions may be compounded by policies at some worksites that require workers to undergo mandatory drug testing following incidents resulting in reported injuries or illnesses, regardless of any evidence of drug use. Several labor representatives described mandatory drug testing policies as a disincentive that affects workers’ decisions to report injuries and illnesses, and 67 percent of health practitioners reported they were aware of this practice at the worksites where they treated workers in 2008."

Source

"Report to Congressional Requesters: Workplace Safety and Health: Enhancing OSHA’s Records Audit Process Could Improve the Accuracy of Worker Injury and Illness Data" United States General Accountability Office, (Washington, DC: October 2009), pp. 17-18.
http://www.gao.gov/new.items/…