In the sister practice of Medical Malpractice much is similar.  The two bodies of law concern the work of professionals, each "treating" or "representing" people.  The laws of negligence apply to both, and both departure and causation must be proved at trial. 

The rules of Summary judgment, well settled, and with a history of their own are widely applied to both bodies of law.  As the statistics show, 95% of all cases are resolved prior to trial, and summary judgment is a significant force in resolution.

Yet, a decision from the Second Department comes as a seismic wave into the rules of summary judgment, with the Appellate Division overruling a well understood principal, and admitting that earlier decisions were so imprecise, that they must be formally overruled.

InStukas v Streiter ;2011 NY Slip Op 01832 ;Decided on March 8, 2011 ;Appellate Division, Second Department ;Leventhal, J., J. the Appellate Division, Second Department holds, in a well reasoned opinion that if defendant makes a prima facie showing that there was no departure, then plaintiff must make a prima facie showing that there was a departure.  If defendant makes a prima facie showing that there was no departure and no causation, then plaintiff must make a prima facie showing that there was a departure as well as causation.  What need not happen is for plaintiff to show both, when defendant only makes a prima facie showing that there was no departure.
 

We don’t remember seeing the AD admit that an earlier decision has absolutely no doctrinal basis:

"To require a plaintiff to address both departure and causation in opposing a defendant’s physician’s prima facie showing as to departure only, conflates these two distinct elements, which have always been treated separately in our jurisprudence involving medical malpractice and negligence in general (see Akins v Glens Falls City School Dist., 53 NY2d at 333; Heller v Weinberg, 77 AD3d 622; Ingrassia v Lividikos, 54 AD3d at 724).

Thus, "candor requires the admission that our past decisions have lacked a precise consistency" (Miller v Miller, 22 NY2d 12, 15). Accordingly, we now clarify that our decisions reflecting the rule stated in Alvarez constitute the more accurate articulation of the applicable standard. To reiterate, in a medical malpractice action, a plaintiff opposing a defendant physician’s motion for summary judgment must only submit evidentiary facts or materials to rebut the defendant’s prima facie showing (see Alvarez v Prospect Hosp., 68 NY2d at 324). This means that if the defendant demonstrates only that he or she did not depart from good and accepted medical practice, the plaintiff need only raise a triable issue of fact as to whether such a departure occurred. The plaintiff is required to raise a triable issue of fact as to causation only in the event that the defendant makes an independent prima facie showing that any claimed departure was not a proximate cause of the plaintiff’s injuries. "