Dr. Freeman will present the conundrum of causation, and why causal determinations can be so difficult and contentious in litigation. He will discuss generally accepted injury causation methods, based on the 3 step injury causation methodology described in the 2016 10th DCA Etherton decision. The 3 steps are as follows: 1) Plausibility [the general causation relationship between the trauma and the injury, utilizing a blend of disciplines including medicine, crash reconstruction, biomechanics, and epidemiology], 2) Temporal proximity [the timing between the trauma and the onset of symptoms indicative of injury], and 3) Lack of a more likely alternative explanation [the “but-for” risk of the injury occurring at the same point in time, but in the absence of the trauma, given the pre-trauma characteristics and history of the plaintiff]. The application of these methods to the most common types of causation disputes, particularly in the context of the defense reliance on non-medical (i.e., biomechanical) testimony, will be described using case examples of traffic crashes and other traumatic causes of spine and head injuries.