More than 100 OSHA standards for controlling workplace hazards contain requirements for worker training to reduce risk factors for injury and disease. Other standards limit certain jobs to workers considered competent by virtue of special training [Cohen and Colligan 1998]. However, the documented outcomes of occupational safety and health training are varied and inconclusive. Moreover, the newly proposed OSHA Occupational Safety and Health Program Rule [DOL 1998] redirects compliance audits to training outcomes and impacts (in the past, such audits focused on hours of training delivered). Given this shift in priority, research will be needed to identify strategies for improving the measurable performance of mandated training programs. Each year, corporate America provides nearly 2 billion hours of training to approximately 60 million employees at a cost of $55 to $60 billion [Industry report 1997]. Effectiveness research can maximize the impact of this investment on worker safety, productivity, and profits. To equip America's workforce with the skills necessary in today's economy, the U. S. Departments of Education and Labor have recently cosponsored several initiatives that reflect the national importance of worker training.