prevent deafness in a surviving patient (thirty percent will become deaf regardless of method or timing of treatment), Dr. O’Mara’s opinion changed. Dr. O’Mara testified, contrary to his deposition testimony and the opening statement in the ease, that Jetta did not have meningitis as of 3:30 p.m. on September 29, 1994, and that Dr. Nelson could and should have prevented Jetta from contracting meningitis by admitting her to the hospital and administering drugs aimed at treating meningitis.3
The district court submitted the ease to the jury. The jury returned a verdict in favor of the Sanfords and against both Dr. Nelson (40% fault) and Crittenden Memorial Hospital (60% fault), awarding damages of $2,500,000 for Jetta Sanford and $1,000,000 for her parents. Crittenden settled with the Sanfords. Dr. Nelson moved for judgment as a matter of law and, in the alternative, a new trial. After expressing serious reservations about the legal adequacy of the medical and scientific testimony introduced at trial, the district court nevertheless denied Dr. Nelson’s motion for judgment as a matter of law. However, the district court granted Dr. Nelson’s alternative motion for a new trial, basing its decision on, among other things, the size of the verdict in favor of Jetta Sanford’s parents and the element of surprise introduced by Dr. O’Mara’s mid-trial change of testimony.
Before the second trial, Dr. Nelson moved for summary judgment, arguing that the testimony of Dr. O’Mara lacked a scientific basis and was therefore insufficient to create an issue of material fact regarding the standard of care or causation. The Sanfords declined to submit further argument or evidence in response to the motion, and instead expressed their desire to appeal from the district court’s grant of a new trial. The district court granted Dr. Nelson’s motion for summary judgment—providing a final, appealable judgment—and the Sanfords lodged this appeal challenging only the district court’s decision to grant a new trial.4
II.
“The authority to grant a new trial ... is confided almost entirely to the exercise of discretion on the part of the trial court.” Allied Chem. Corp. v. Daiflon, Inc., 449 U.S. 33, 36, 101 S.Ct. 188, 191, 66 L.Ed.2d 193 (1980). We review the district court’s decision for a clear abuse of that discretion. Pitts v. Electro-Static Finishing, Inc., 607 F.2d 799, 803 (8th Cir.1979). Where, as here, the size of the verdict provided a basis for a new trial, our review is extraordinarily deferential. It has long been our opinion that the matter is:
basically, and should be, ... for the trial court which has had the benefit of hearing the testimony and of observing the demeanor of the witnesses and which knows the community and its standards; ... and that we shall continue to review, as we have said before, not routinely and in every case, but only in those rare situations where we are pressed to conclude that there is ‘plain injustice’ or a ‘monstrous’ or ‘shocking’ result.
Solomon Dehydrating Co. v. Guyton, 294 F.2d 439, 447-48 (8th Cir.1961) (Blackmun, J.); Nodak Oil Co. v. Mobil Oil Corp., 533 F.2d 401, 411 (8th Cir.1976).
Although the appropriateness of a new trial is a federal procedural question decided by reference to federal law, Pitts, 607 F.2d at 802, in determining whether a state law claim damage award is excessive, state case law guides our inquiry. England v. Gulf & Western Mfg. Co., 728 F.2d 1026, 1029 (8th Cir.1984). Under Arkansas law, a
3
Dr. O’Mara testified that Jetta should have been tested for meningitis, and that even if the results were negative she should have been treated with intravenous antibiotics or a very strong antibiotic generally used after meningitis has developed. Dr. Nelson’s medical expert witness acknowledged that there was some “logic" to Dr. O’Mara’s causation theory, and that one particularly powerful antibiotic, Rocephin, might have prevented meningitis. There was further defense testimony that, for reasons noted at trial, Rocephin was not used in standard practice as a preventative.
4
The Sanfords’ decision to neither oppose the motion for summary judgment nor appeal the district court's order granting it gives rise to an inference that they were unable to adequately respond. Nevertheless, we will give the San-fords the benefit of the doubt on this point.