The continuity principle: a unified approach to disaster and trauma.

The continuity principle stipulates that through all stages of disaster, management and treatment should aim at preserving and restoring functional, historical, and interpersonal continuities, at the individual, family, organization, and community levels. Two misconceptions work against this principle and lead to decisional errors: the "abnormalcy bias" which results in underestimating victims' ability to cope with disaster, and the "normalcy bias" which results in underestimating the probability or extent of expected disruption. This article clarifies these biases and details the potential contributions of the continuity principle at the different stages of the disaster.