"Errors and violations committed by those at the sharp end are common enough in organizational accidents, but they are neither necessary nor sufficient causes (...)
Latent conditions, however, are always present in complex systems. They relate to (...) the everyday business of management. (...)
Safety is not a separate issue. (...)
[Latent conditions] are an inevitable product of strategic decisions."

- James Reason (1997, p. 36).

Robert K. Merton's (1957; Social Theory and Social Structure) concepts of manifest and latent functions and dysfunctions refer to the intended and unintended consequences of social actions or structures. In James Reason's text above, the concept of 'latent conditions' is used to describe unintended consequences that arise from the everyday business of management.

James Reason highlights that safety is not a separate issue and is often impacted by latent conditions that arise from strategic decisions made by management.  These decisions can produce latent conditions that contribute to organizational accidents. These conditions are an inevitable product of strategic decisions and are always present in complex systems.

These conditions can lead to errors and violations by those at the sharp end of the organization. While these errors and violations are common, they are not the necessary or sufficient causes of organizational accidents. Instead, it is the latent conditions that should be the focus of management, in order to improve safety.

In sum: 

• The manifest function of a primary process is e.g. delivering product to market.
• The latent function is a positive unintended consequence of strategic decisions made by management.
• The dysfunction is a negative unintended consequence of latent conditions.