Over half of serious injuries and fatalities involve unexpected changes in the work process or environment. In our earlier project, we measured how well workers notice and assess change. This next project will explore what happens when attention is divided by other tasks and competing motivations. We’ll examine what changes workers notice, which they miss, and why; how the risk associated with change is assessed; and what ultimately drives the decision to stop work. We’ll also study crew dynamics and how the type of information about the change affects how we respond. Ultimately, this research will explore why high-risk changes are sometimes discounted and identify interventions that highlight them so people clearly recognize when a change is critical and could cause a SIF.