On September 30, 2016 the Tenth District of the Ohio Court of Appeals decided Chilton-Clark v. Fishel, 2016-Ohio-7135. The case confirms two important aspects of professional liability law as applied to accountants. First, regardless of how a plaintiff characterizes the claims, courts will consider it a professional negligence claim if the factual basis of the claims is the professional relationship between the parties. Second, in most circumstances, a plaintiff must present expert testimony in order to pursue the professional negligence claim. A plaintiff could theoretically sue a professional under a number of different causes of action. For example, a plaintiff may try to disguise a professional negligence lawsuit as a contract claim alleging the professional breached the retention agreement with the client. In cases against attorneys and physicians, these claims are typically subsumed within the malpractice claim when the factual basis of the claims arises out of the professional relationship. The court in Chilton-Clark extended this rule to actions against accountants, holding that claims for breach of contract, breach of fiduciary duty and negligence should be considered as claims of "professional negligence" subject to the same rules as malpractice claims because all three causes of action flowed from the professional relationship between the plaintiff and the accountant. This is important because a malpractice action requires a plaintiff to present expert testimony to establish that the professional's actions or omissions fell below the standard of care of a reasonably prudent professional within the applicable industry. Chilton-Clark makes it clear that this rule also applies to professional negligence claims against accountants. The plaintiff must either (1) provide expert testimony to prove that the professional's conduct breached the duty owed to the client or patient, or (2) show that expert testimony is not required because the conduct is within the comprehension of a lay person and requires only common knowledge and experience to understand it. Furthermore, if a plaintiff simply fails to present expert testimony at the trial level, he or she cannot argue on appeal that the inquiry is within common, ordinary, and general experience of most people. Thus, a plaintiff must either make that argument at trial or risk waiving it on appeal. Either way, in all but rare cases, expert testimony is required to support allegations of professional negligence against accountants.