Does the failure to call treating physicians prejudice the outcome of a trial?

Mink attempts to distinguish Smith v. Covell on the ground that the reference to the failure to call treating physicians in that case was only one of a number of errors that had the cumulative effect of prejudicing the outcome of the trial. Nothing in that case suggests that the court only reversed and remanded the judgment based on other trial court errors. Mink also notes that in Smith v. Covell a new trial was granted solely on the issue of damages. Before the initial trial, the defendant had conceded the issue of liability, and the only issue for trial was damages.