In this products-liability case Carol Ann Setter alleges that she was injured by wearing a Dalkon Shield, an intrauterine contraceptive device manufactured by the defendant A.H. Robins Co. The jury found that the device did not have a design defect, and that Robins (1) adequately warned physicians of the risks associated with the Dalkon Shield, and (2) was not negligent in the design, manufacture, testing, or inspection of the Dalkon Shield. On this verdict judgment was entered for defendant. Setter appeals, arguing that certain documents were wrongly excluded by the District Court1, that one of defendant's counsel "tampered" with her expert witness, and that the District Court2 erred in denying her motion for partial summary judgment based on a theory of collateral estoppel. We affirm.

Most of the documents Setter claims were wrongly excluded had been admitted in a previous trial, Strempke v. A.H. Robins, Co., Inc., No. 3-80 Civ. 169 (D.Minn. June 6, 1983), as exhibits accompanying the testimony of one of Strempke's experts, Dr. Howard Tatum. Dr. Tatum's testimony was read into the record by plaintiff in this trial. At least three of the exhibits plaintiff claims were wrongly excluded were actually admitted (Exs. 331, 392a, and 436).3 The substance of the other exhibits which accompanied Dr. Tatum's testimony was covered both in Dr. Tatum's testimony and in Dr. Robert Diamond's testimony. Dr. Diamond was one of plaintiff's experts, and defense counsel used some of Dr. Tatum's work in cross-examining Dr. Diamond.

The transcript of the testimony of Dr. Daniel Mishell, who also testified in the Strempke case, was also read to the jury in Setter's trial. Plaintiff offered, with Dr. Mishell's testimony, a written analysis by a panel of doctors including Dr. Mishell. The only ground plaintiff offers for the admission of the exhibits accompanying the testimony of Dr. Mishell and Dr. Tatum is that they were admitted in the Strempke trial. We do not feel that the court abused its discretion in excluding those exhibits, since their essence was before the jury already in the form of other evidence.

The other exhibits plaintiff claims were wrongly excluded were medical reports by Dr. Diamond and Dr. Underwood. Plaintiff says these reports were part of a larger group of documents and that the parties had stipulated to their admission, subject to some "sanitizing" by defense counsel. The substance of these doctors' reports was covered by the evidence which was admitted. The District Court acted within its discretion in excluding them. It is in a much better position than we are to make informed judgments on this sort of evidentiary question.

Plaintiff's claim that defense counsel improperly spoke with her expert witness was a brief topic of an in-chambers discussion. She requested no relief, and the District Court made no findings on this accusation. Hence, there is nothing for us to review.

The Strempke trial ended in a jury verdict for the plaintiff. Setter moved for summary judgment on the issue of liability, claiming that Robins should be collaterally estopped to relitigate the questions of design defect and negligence by the judgment entered against it in Strempke. Setter's request was for the application of what has been called offensive nonmutual collateral estoppel. The estoppel sought was nonmutual because Setter, who was not a party to the Strempke case, would not have been bound had judgment been rendered for Robins in that case. She nevertheless asks that she be given the benefit of the judgment previously rendered against Robins. And the requested estoppel is offensive because the plaintiff here, Setter, is seeking to foreclose the defendant Robins from litigating an issue that it previously litigated unsuccessfully in an action with another plaintiff.

The leading Supreme Court case on nonmutual collateral estoppel is Parklane Hosiery Co. v. Shore, 439 U.S. 322, 99 S. Ct. 645, 58 L. Ed. 2d 552 (1979). In recognizing the concept of offensive collateral estoppel, the Supreme Court said:

[T]he preferable approach ... is not to preclude the use of offensive collateral estoppel, but to grant trial courts broad discretion to determine when it should be applied. The general rule should be that in cases where ... the application of collateral estoppel would be unfair to a defendant, a trial judge should not allow the use of offensive collateral estoppel.

Id. at 331, 99 S.Ct. at 651.

Under this rule, the District Court's decision not to apply collateral estoppel here can be reversed only if there has been an abuse of discretion. We find no such abuse. The principal reason given by the District Court for ruling against the plaintiff on this issue was that Robins had won some previous judgments on the question of liability, as well as losing some. If Strempke had been the only previously tried case, a different question would have been presented, but it was not. At the time of the District Court's ruling, Robins had tried twenty-one Dalkon Shield cases to completion. Twelve of these cases had resulted in a defendant's verdict or decision. One had ended in a hung jury, and Robins had lost eight. This is one of the situations in which the Supreme Court in Parklane indicated that trial courts might choose to refuse collateral-estoppel effect to a previous judgment against a defendant. "Allowing offensive collateral estoppel may ... be unfair to a defendant if the judgment relied upon as a basis of the estoppel is itself inconsistent with one or more previous judgments in favor of the defendant." 439 U.S. at 330, 99 S.Ct. at 651 (footnote omitted). In the circumstances of this case this factor alone is sufficient to persuade us that the District Court did not abuse its discretion. Defendant had won a majority of the litigated judgments on the question of Dalkon Shield liability at the time of the District Court's ruling, and plaintiff has not suggested any special circumstances that should have led the District Court to disregard or otherwise discount those cases in which defendant had prevailed.

Other factors mentioned by the District Court also support the choice it made. Judge Alsop, who ruled on the motion for partial summary judgment, had tried the Strempke case himself. He was intimately familiar with the proceedings therein, and he took the view that the Strempke verdict was ambiguous. The verdict, for example, did not specify which of several possible types of negligence the jury had found. An estoppel should be reasonably certain, and if there is a serious ambiguity as to what the previous court or jury decided, it is unfair to deny a party its right to contest the merits of the question in the instant case. Collateral estoppel applies only to issues of fact or law necessarily decided. See Hardy v. Johns-Manville Sales Corp., 681 F.2d 334, 345 (5th Cir.1982). We defer to Judge Alsop's familiarity with and construction of the verdict and judgment in the Strempke case.

Finally, the District Court properly observed that application of offensive collateral estoppel in the present situation would not necessarily promote judicial economy. See Parklane Hosiery, 439 U.S. at 329-30, 99 S.Ct. at 650-51. Even if collateral estoppel were invoked here, little court time would be saved, because most plaintiffs, including Setter, claim punitive damages in Dalkon Shield cases, and the same facts, or most of them, that would have been relevant on the issue of liability would still have to come in and be considered by the court or jury on the issue of exemplary damages.

In short, there was no abuse of discretion in the District Court's refusal to preclude Robins from litigating the question of liability against Setter. Nor have we found any reversible error in the conduct of the trial. The judgment of the District Court is therefore