In the broadest sense, safety data include reports of events, such as accidents and incidents, inspection results, reports of enforcement actions or other sanctions, and other data which characterize the activities of the air transportation system. It must be noted that only accidents (and some incidents) involve measurable harm to persons or property, and that many types of incidents are reported to FAA by the carriers themselves.
It should be noted that there is no consensus among researchers and participants in the aviation industry about what exactly constitutes "safety data." This lack of consensus was strongly expressed in the comments to the initial draft of this report. Although accidents are universally regarded as events that should be avoided and eliminated if possible, there is little or no statistical evidence for U.S. domestic commercial aviation that other forms of "safety data"-incidents, surveillance results, or enforcement actions-serve as predictors of future accidents or are correlated with accident rates for individual carriers. While the remainder of this section discusses types of data that are commonly regarded as relevant to safety concerns and to the fulfillment of FAA's safety responsibilities, the exact nature of the relationships between these data and the safety of airline operations remains the subject of research in the aviation community.
More details: