Abstract
This essay argues for the importance of error as an organizing concept in the management of hazardous technical systems to high levels of reliability and safety. The concept of "error" has been essential to the development of high reliability organizations (HROs). As practiced in HROs, error management has also been an important strategy for the management of uncertainty. "Uncertainty" has been conceived by some analysts as a condition that can convey little or no reliable information about its own boundary conditions or its specific threat to the operation of complex systems. The argument here is that uncertainty is differentiated and specified in HROs and provides important information in relation to error. Uncertainty does not, in the special context of HROs, end the possibility and practice of reliable management. In fact, error in HROs can be a starting point for the further analysis of ways in which uncertainty itself can be managed reliably. But the argument offered here does not mean that uncertainty does not challenge reliability in other settings. The COVID-19 pandemic is offered as an example of how uncertainties may invalidate even the application of "reliability" as a performance standard in certain domains of management and policy.