What is the test for a jury to determine whether a professional negligence or malpractice occurred in the context of a criminal case?

Reinforcing this conclusion are the pragmatic difficulties that would arise from simply overlaying criminal malpractice actions with the civil malpractice template. In civil actions, carrying the burden on causation is relatively straightforward and comprehensible for the jury, even if it necessitates a "trial within a trial." The factual issues in the underlying action are resolved according to the same burden of proof, and the same evidentiary rules apply. Thus, it is reasonably possible for the malpractice jury to assess whether and to what extent counsel's professional lapse compromised a meritorious claim or defense. (See Glenn v. Aiken, supra, 569 N.E.2d at p. 787.)