Carol Thompson and her children sued the Georgia Department of Transportation after a collision caused severe injuries. The Department moved to dismiss based on sovereign immunity, and the trial court denied the motion. The Georgia Court of Appeals held that the trial court had applied the wrong legal standards when evaluating whether the plaintiffs established a waiver of immunity and whether their expert affidavit was sufficient. The court distinguished the standard for an expert affidavit in a professional-negligence claim from the separate standard governing sovereign-immunity dismissal. It vacated the order and remanded for reconsideration under the proper standards, and it disapproved an earlier statement to the extent it conflated those inquiries.