SummaryDisasters typically strike quickly and cause great harm. Unfortunately, because of the spontaneous and chaotic nature of disasters, the psychological consequences have proved exceedingly difficult to assess. Published reports have often overestimated a disaster's psychological cost to survivors, suggesting, for example, that many if not most survivors will develop posttraumatic stress disorder (PTSD); at the same time, these reports have underestimated the scope of the disaster's broader impact in other domains. We argue that such ambiguities can be attributed to methodological limitations. When we focus on only the most scientifically sound research-studies that use prospective designs or include multivariate analyses of predictor and outcome measures-relatively clear conclusions about the psychological parameters of disasters emerge. We summarize the major aspects of these conclusions in five key points and close with a brief review of possible implications these points suggest for disaster intervention.1. Disasters cause serious psychological harm in a minority of exposed individuals. People exposed to disaster show myriad psychological problems, including PTSD, grief, depression, anxiety, stress-related health costs, substance abuse, and suicidal ideation. However, severe levels of these problems are typically observed only in a relatively small minority of exposed individuals. In adults, the proportion rarely exceeds 30% of most samples, and in the vast majority of methodologically sound studies, the level is usually considerably lower. Among youth, elevated symptoms are common in the first few months following a high-impact disaster, but again, chronic symptom elevations rarely exceed 30% of the youth sampled.2. Disasters produce multiple patterns of outcome, including psychological resilience. In addition to chronic dysfunction, other patterns of disaster outcome are typically observed. Some survivors recover their psychological equilibrium within a period ranging from several months to 1 or 2 years. A sizeable proportion, often more than half of those exposed, experience only transient distress and maintain a stable trajectory of healthy functioning or resilience. Resilient outcomes have been evidenced across different methodologies, including recent studies that identified patterns of outcome using relatively sophisticated data analytic approaches, such as latent growth mixture modeling.3. Disaster outcome depends on a combination of risk and resilience factors. As is true for most highly aversive events, individual differences in disaster outcomes are informed by a number of unique risk and resilience factors, including variables related to the context in which the disaster occurs, variables related to proximal exposure during the disaster, and variables related to distal exposure in the disaster's aftermath. Multivariate studies indicate that there is no one single dominant predictor of disaster outcomes. Rather, as with traumatic life events more generally, most predictor variables exert small...