Sorenson, J.H., 1991: When shall we leave? Factors affecting the timing of evacuation departures. International Journal of Mass Emergencies and Disasters, 9(2), 153-165.

This is one of few articles that looks at the timing of evacuations, specifically when and why people evacuate during hazards. The author statistically examined individual variation in the timing of warnings being disseminated and when the individual evacuated. The Nanticoke, PA hazardous materials fire is used as a case study to analyze the variations in how and when a warning was received as well as when people began evacuating. A prominent finding was that the time of evacuation varied by how an individual received the warning, confirming that the time of warning differed by warning type (sirens, route, media, informal, etc.). Other factors that are related to time of warning receipt are how close the emergency site is to the individual and the type of structure which the individual inhabits. Personalized warnings were found to greatly enhance the mobilization time, presenting an issue to emergency managers who require more time to personalize a warning. Factors that were not significant in affecting the timing of evacuation are age and family size. The article ends with recognition that researching why people do not respond may be just as valuable as looking at why people do respond (i.e. evacuate).