In Beasley v. Northside Hosp., 289 Ga. App. 685 (658 SE2d 233), (2008), the Court emphasized that the pertinent causation testimony in the expert affidavit included "no assessment of the likelihood that the hospital's alleged negligence caused plaintiff's injuries, no basis for the expert's conclusion, and no expression of probability that the expert's conclusion was accurate" (id. at 689-690); rather the only testimony as to the expert's level of certitude on the pertinent causation issue was later expressed by the expert in his deposition as being no more than a possibility.