On March 24, 2006, the French Minister of Environment asked the Committee for Prevention and Precaution (CPP), an independent multidisciplinary committee created in 1996, to conduct a methodological analysis of operational feedback of natural and technological disasters to determine if France is equipped to collect the information and data necessary for the assessment, and optimal management of a disaster and its consequences. The Committee's analysis was based on the testimony it heard from 13 experts--scientists and representatives of associations and advocacy groups--and its review of the literature, including operational feedback reports. Its response to the Minister focused on the assessment of the health, social, environmental, and economic impacts of disasters and on their operational feedback (defined as the systematic analysis of a past event to draw lessons for the management of the risk), as practiced in France. It presents the results of the literature review about the consequences of disasters, expert's views on the current utility and limitations of impact assessments and operational feedback, the CPP's discussion of these results, and its recommendations to improve impact assessment and operational feedback of disasters. These recommendations cover preparation for and activation of data collection and operational feedback, financial provisions, coordination of stakeholders, education and training in disaster preparedness, and the distribution and use of data from operational feedback.