Court Opinion

ID: 2709449
Source: CourtListenerOpinion
Date Created: 2014-08-05 15:15:51.416451+00
Date Added: 2024-06-11T10:01:25.885902
License: Public Domain

In the

    United States Court of Appeals
                 For the Seventh Circuit
No. 12-2984

BRANDON STOLLINGS,
                                                  Plaintiff-Appellant,

                                  v.

RYOBI TECHNOLOGIES, INC. and ONE
WORLD TECHNOLOGIES, INC.,
                                               Defendants-Appellees.

         Appeal from the United States District Court for the
           Northern District of Illinois, Eastern Division.
            No. 08 C 4006 — Gary S. Feinerman, Judge.

      ARGUED APRIL 4, 2013 — DECIDED AUGUST 2, 2013

   Before MANION, TINDER, and HAMILTON, Circuit Judges.
     HAMILTON, Circuit Judge. On May 9, 2007, Brandon Stollings
lost an index finger and portions of other fingers in a table saw
accident. Stollings sued the saw manufacturer, Ryobi Technolo-
gies, alleging that Ryobi defectively designed the saw because
it failed to equip the saw with either of two safety features: a
riving knife—a small blade that holds the cut in the wood open
to prevent kickbacks—and automatic braking technology—a
2                                                    No. 12-2984

safety system that automatically stops the saw blade upon
contact with human tissue. Stollings contends either safety
feature would have prevented the accident. A jury returned a
verdict in favor of Ryobi. Stollings has appealed.
    Stollings argues that the district court made three reversible
errors: (1) failing to stop Ryobi’s counsel from arguing to the
jury that Stollings’s counsel brought the case as part of a joint
venture with the inventor of the automatic braking technology
to force saw manufacturers to license the technology, and
admitting hearsay evidence to support this improper argu-
ment; (2) excluding the testimony of one of Stollings’s expert
witnesses; and (3) giving two erroneous jury instructions. We
find that Ryobi’s joint venture argument was improper and
prejudicial, so we vacate the judgment and remand for a new
trial. Because the remaining issues are likely to resurface if the
case is retried, we address them and conclude that the court
erred in excluding the expert testimony and in giving the jury
a sole proximate cause instruction where Ryobi was not
asserting a comparative fault defense or blaming a third party.
I. The Improper Attack on Counsel’s Motives
    A. The Accident and Power Saw Safety
    We address first Ryobi’s improper attack at trial on the
motives of plaintiff’s counsel, which requires us to provide the
background on the accident and power saw safety. Stollings
was injured while operating a Ryobi Model BTS20R table saw.
The immediate cause of the injury was a common
woodworking hazard known as a kickback. A kickback occurs
when the kerf, the gap in the wood created by a saw’s cut,
closes around the saw blade in such a way that the force of the
No. 12-2984                                                       3

spinning blade throws the wood back at the user. If the saw
operator is holding onto the wood, the unexpected movement
can sometimes force the operator’s hand into the spinning saw
blade. This is what happened to Stollings.
    Saw manufacturers include safety features to help protect
users from kickback injuries. Ryobi equipped the saw with a
“3-in-1” guard safety system. This safety system has three
components: a splitter, anti-kickback pawls, and a blade
shield. The splitter is a piece of plastic that rests behind the saw
blade to prevent the kerf from closing around the saw. The
anti-kickback pawls are serrated pieces of metal attached to the
sides of the splitter that rest on the wood as it moves through
the cut to prevent the wood from moving backwards. And the
blade shield is a piece of plastic that covers the top of the blade
to prevent the user’s hands from coming into contact with the
blade. This system complied with the applicable guarding
standards published by Underwriters Laboratory—a private
company that sets industry safety standards—and the applica-
ble federal Occupational Safety and Health Administration
regulations.
    The 3-in-1 system is effective at reducing injuries when
used correctly, but it has shortcomings. The principal problem
is that many saw users deliberately disable the 3-in-1 guard
system. There are two reasons for this. The plastic guard makes
certain cuts more difficult to complete, and the guard can
become clouded by sawdust and other material, thus obstruct-
ing the user’s view of the saw blade as it cuts. The 3-in-1
system is also interconnected. When a user removes the guard,
he must also remove the splitter and the anti-kickback pawls,
leaving the saw blade without any kickback protection. That is
4                                                     No. 12-2984

what Stollings did. Despite warnings on the saw about the
dangers of operating the saw without the guard, Stollings
removed the guard and operated the saw without the safety
protection. Before a reader concludes that this fact decides the
case, though, we should note that Ryobi’s former chief engi-
neer testified that he had removed the 3-in-1 system on his
own home saw and had instead installed a riving knife.
    The jury heard evidence that Ryobi could have equipped its
saw with two alternative safety features. The first is a riving
knife, which is a cheap piece of metal or plastic similar to a
splitter. Like a splitter, a riving knife rests behind the blade and
holds the kerf open. Unlike the splitter in the 3-in-1 guard
system, a riving knife is typically positioned closer to the saw
blade, making it more effective at preventing kickbacks. Most
important, it is independent of the guard system, so the user
has no reason to remove it.
    The second additional safety feature is an automatic
braking system, colorfully known as flesh detection technol-
ogy. The automatic braking system prevents injury by stop-
ping and retracting the blade at the moment the blade contacts
flesh. The technology works by detecting the human body’s
electrical current. When an operator’s flesh contacts the blade,
the body’s electrical current triggers the safety system, which
applies a brake and retracts the blade beneath the cutting
surface. The saw stops within a few milliseconds, fast enough
in most cases to leave the operator with only a minor, superfi-
cial wound. The technology, however, is not cheap. It would
add somewhere between $50 and $150 to the cost of a table
saw.
No. 12-2984                                                   5

    Stephen Gass developed the automatic braking system in
1999. Gass patented the technology and then attempted to
license it to table saw manufacturers, including Ryobi. Gass
and Ryobi entered negotiations over a licensing agreement, but
the negotiations fell through and Ryobi never licensed Gass’s
technology. Stollings maintains that Ryobi and other manufac-
turers decided not to license Gass’s technology for fear of
product liability exposure on saws that did not have the
technology. Ryobi contends Gass’s terms were unreasonable
and the technology was too expensive and unproven. In 2005,
Gass founded a competing company named SawStop to
manufacture and sell table saws that include his automatic
braking system. Gass testified at trial as one of Stollings’s
expert witnesses about the feasibility and effectiveness of the
automatic braking system. He did not ask for or receive
compensation for his testimony.
   B. The Trial Attack on Plaintiff’s Counsel
    In addition to the arguments one would expect Ryobi to
make—that the saw complied with industry safety standards
and that Stollings was responsible for his injury because he
failed to use the 3-in-1 safety system—Ryobi framed the case
for the jury as a joint venture between Gass and Stollings’s
attorneys—Mr. Carpinello and Mr. Sullivan—to coerce Ryobi
and other saw manufacturers to license and use Gass’s auto-
matic braking technology. The district judge referred to this as
Ryobi’s “conspiracy” theory, though the word conspiracy was
not used in the presence of the jury.
    Ryobi’s attack on the motives of Stollings’s counsel began
in its opening statement. More than half of it was dedicated to
6                                                  No. 12-2984

the argument that the case was being brought by Stollings’s
attorneys to intimidate the saw manufacturers. The implication
of the argument was that the jury should not let Stollings’s
counsel and Gass play them for chumps. Here are some
examples from Ryobi’s opening statement:
     “The evidence is going to establish that there’s a
     joint venture between Mr. Carpinello and Mr.
     Stephen Gass …, whereby Mr. Carpinello will file
     product liability lawsuits against manufacturers that
     don’t pay Mr. Gass a royalty for his patent … .”
     “Mr. Carpinello has filed over 90 of these product
     liability lawsuits … and Mr. Gass is his expert
     witness in every one of those cases … .”
     “So what we have here is a patent IP case, an intel-
     lectual property case, masquerading as a personal
     injury case … .”
     “There’s something going on below the surface and
     that’s why, in [this] opening statement, I want you
     to be aware of what is going on here. So the joint
     venture that exists in this case is part of an overall
     strategy to force the manufacturers to pay Mr. Gass
     for his technology … .”
     “So what are we talking about here? We’re talking
     about an attempt to intimidate manufacturers to pay
     [Gass] a royalty so they don’t have to be sued by Mr.
     Carpinello all over the country because they’re
     making a saw that complies with what the design
     standards required.”
No. 12-2984                                                       7

    At the beginning of the opening statement, Stollings’s
counsel objected, arguing that these insinuations were prejudi-
cial and not based on any evidence. Ryobi responded that it
had evidence of the supposed joint venture. The judge permit-
ted Ryobi to continue, informing the jury that opening state-
ments are not evidence. Ryobi’s “evidence” was an article
about Gass from The Oregonian newspaper. Stollings had
made a valid hearsay objection to the article before trial, but
the court permitted Ryobi to use the article during its opening
statement.
    After the court overruled Stollings’s objection, Ryobi’s
counsel continued: “The evidence will establish that there’s a
joint venture between Mr. Carpinello and Mr. Gass … .”
Ryobi’s counsel then told the jury about the Oregonian
newspaper article and argued that it was evidence of the joint
venture. Ryobi’s counsel used a blown-up version of the article
to draw the jury’s attention to what Ryobi believed were the
critical points. Pointing to a section of the article that said Gass
had been approached by products liability lawyers, Ryobi’s
counsel said: “Oh, this thing about the joint venture. Gass says
he has been approached by lawyers looking to launch product
liability suits that ultimately could force companies to license
his technology. That’s part of his strategy.” Ryobi’s counsel
then concluded: “And that’s the case that Mr. Carpinello has
filed here, just like Mr. Gass said, to launch product liability
suits that will ultimately force companies to license his technol-
ogy. Part of a game plan to sue the manufacturers all across the
country, have Mr. Carpinello coming after the manufacturer
alleging to a jury that the product is defective and unreason-
ably dangerous … .”
8                                                    No. 12-2984

    Throughout the trial, Ryobi continued to link the motives
of Stollings’s attorneys with Gass’s desire to persuade saw
manufacturers to license his technology. Ryobi’s counsel made
repeated references to the number of saw cases in which
Stollings’s attorneys were involved, asked witnesses whether
the attorneys were involved in other cases in which the
witnesses had testified, and read the names of Stollings’s
attorneys off of deposition transcripts from other cases.
    Ryobi also emphasized the joint venture theme in its closing
argument. “What’s going on in this case?” counsel asked
rhetorically: “This is that Oregonian newspaper article. Why is
that significant? Because these are quotes from Mr. Gass … and
he doesn’t deny these quotes.” Ignoring the facts that the
article did not directly quote Gass and that Gass in fact had
denied that the article directly quoted him, Ryobi’s counsel
continued:
       Gass says he has been approached by lawyers
       looking to launch product liability suits that
       ultimately could force companies to license his
       technology … . I didn’t say that. That’s what
       Gass says. Approached by lawyers to launch
       product liability suits that ultimately could force
       companies to license his technology. That’s why
       he has—has been sitting here with his partner
       throughout this trial, not charging Mr.
       Carpinello or Mr. Sullivan to be here. And he has
       been their expert in all of these cases that they’ve
       filed against table saw manufacturers … .
No. 12-2984                                                     9

    By the end of the trial, the district judge realized that
Ryobi’s argument had gone too far. The judge had always
recognized that Ryobi was entitled to attack the credibility of
Gass for bias, but earlier in the trial the judge had said that an
attack on the motives of Stollings’s lawyers “would be out of
bounds.” At that time the judge did not believe that such an
attack had occurred. Later in the trial, after reviewing the
transcripts, however, the judge recognized that the attack had
also been aimed directly against Stollings’s lawyers.
    The judge then concluded that it would likely be reversible
error if he did not allow Stollings to rebut the accusations. Tr.
at 1653. Stollings asked for free rein to discuss the facts of the
other saw cases to which Ryobi referred, while Ryobi argued
that any reference to the other saw cases would be unduly
prejudicial. The judge’s solution was an instruction telling the
jury that, of the cases Ryobi referred to, only one was decided
on the merits, and it resulted in a verdict for the plaintiff.
Unfortunately, however, the instruction also told the jurors
that they were free to consider Ryobi’s “joint venture” theory
in reaching their decision. The instruction said in relevant part:
       You’ve heard mention of other table saw cases
       filed by Mr. Carpinello and Mr. Sullivan against
       various table saw manufacturers in which Dr.
       Gass served as an expert witness. Only one of
       those other table saw cases has been tried to
       verdict. That verdict was in favor of the plaintiff
       in that case. You are not to consider, discuss, or
       speculate about which manufacturer was the
       defendant in that case; nor may you consider,
       discuss, or speculate about the brand or model of
10                                                   No. 12-2984

        the saw in that case; nor may you consider,
        discuss, or speculate about where or when that
        trial took place. You are not to consider the
        verdict in that case as having any direct bearing
        on whether the table saw in this case was
        negligently designed or unreasonably dangerous
        … . In the rest of the table saw cases, no court or
        jury has made any decision one way or the other
        regarding the merits of those cases … . You may
        consider this information about the other table
        saw cases solely for the purposes of: 1.
        Evaluating the weight of Dr. Gass’s testimony;
        and 2. Considering whether the other table saw
        cases brought by Mr. Carpinello and Mr.
        Sullivan in which Dr. Gass served as an expert
        witness were brought to force table saw
        manufacturers to license table saw technology.
        The weight to be given to this information is up
        to you.
     C. Analysis of the “Joint Venture” Argument
    Stollings argues that Ryobi’s attacks on the motives of his
counsel deprived him of a fair trial, which requires him to
show that Ryobi’s argument was improper and that any errors
the district court made in permitting improper lines of
argument were not harmless. See Fed. R. Civ. P. 61; Perry v.
Larson, 794 F.2d 279, 285 (7th Cir. 1986) (to require a new trial,
error must be “substantial enough to deny [party] a fair trial”).
If an argument is improper, five factors are relevant as we
consider whether the improper argument deprived a party of
a fair trial: (1) the nature and seriousness of the argument, (2)
No. 12-2984                                                               11

whether the statement was invited by the opposing party, (3)
whether the statement could be rebutted effectively, (4)
whether an effective curative instruction was given, and (5) the
weight of the evidence. See United States v. Klebig, 600 F.3d 700,
720-21 (7th Cir. 2009).1 Stollings contends that Ryobi’s attack on
the motives of his counsel—exacerbated by the admission of
hearsay evidence and an improper summation of the evidence
during Ryobi’s closing argument—was improper and
sufficiently prejudicial to deprive him of a fair trial. We agree.
   Ryobi’s argument that plaintiff’s counsel brought this suit
as part of a joint venture with Gass to force Ryobi to license
Gass’s technology was improper. The first problem with this
argument is that it is not relevant to any issue in dispute. The
suggestion that the case was an intellectual property case
“masquerading as a personal injury case” did not bear on
whether Ryobi designed and sold a defective product. How
does a statement about counsel’s motive help a jury decide
whether there was an injury? A duty? A breach of that duty?
Or causation?
    The argument worked by directing the jury’s focus away
from the elements of the case to an extraneous and
inflammatory consideration. It said to the jury, don’t let
Stollings’s lawyers trick you into finding Ryobi liable for his

1
   These factors have been developed in criminal cases like Klebig to
determine whether prosecutorial misconduct prejudiced a defendant. The
factors are equally valuable in evaluating civil trials, at least when timely
objections are made, as they were here. If there is any difference in the
harmless error determination between criminal and civil trials, it is in the
strength of the showing required to demonstrate that an error is harmless,
not in the relevant considerations.
12                                                    No. 12-2984

injury because this case is really not about Stollings, it’s about
Gass and his technology. Such an argument aimed at a party’s
counsel is improper and risks depriving the party of a fair trial.
See Gruca v. Alpha Therapeutic Corp., 51 F.3d 638, 645-46 (7th
Cir. 1995) (remanding for new trial; improper for products
liability defendant to highlight negligence of third party when
third party’s conduct was not at issue in case); Davis v. FMC
Corp., 771 F.2d 224, 233 (7th Cir. 1985) (same); see also United
States v. Xiong, 262 F.3d 672, 675 (7th Cir. 2001) (noting attacks
on counsel “can prejudice the [opposing party] by directing the
jury’s attention away from the legal issues”).
     The second problem is that no admissible evidence
supported the argument. Ryobi based its accusation solely on
an article about Gass published in the Oregonian newspaper,
and the article was inadmissible hearsay. The article reported:
“Gass says he has been approached by lawyers looking to
launch product liability suits that ultimately could force
companies to license his technology.” Ryobi used the article to
assert that Gass said he was working with product liability
lawyers to force manufacturers to license his technology. This
is classic hearsay: an out-of-court statement offered to prove its
truth—that is, that Gass made the statement. See Chicago
Firefighters Local 2 v. City of Chicago, 249 F.3d 649, 654 (7th Cir.
2001) (newspaper article was inadmissible hearsay when
offered as proof of article’s contents). Federal Rule of Evidence
802 plainly prohibited admission of the article for this purpose.
   The rules of evidence prohibit most hearsay evidence
because it is so often unreliable. This concern is illustrated by
looking at the ambiguities in the Oregonian article. The author
No. 12-2984                                                              13

did not use quotation marks to indicate that he was quoting
Gass, so it is unclear even whether the author was asserting
that the conclusion about forcing companies to license Gass’s
technology was Gass’s conclusion or the author’s. (On cross-
examination Gass denied that the author was quoting him.) It
is also ambiguous whether the article said that the lawyers
launched the product liability suits for the purpose of forcing
the companies to license Gass’s technology or whether such
licensing might simply be a consequence of the lawsuits. The
statements in the article were made out of court, and the
declarant (the reporter) was not available for Stollings to cross-
examine. The judge should have excluded the article.2
    We need not decide if the improper admission of the
hearsay article and its use in the opening statement were
reversible error on their own. Cf. Jordan v. Binns, 712 F.3d 1123
(7th Cir. 2013) (finding that some errors in admitting hearsay
testimony were harmless in light of entire trial record). This
entire line of argument was sufficiently prejudicial to warrant
a new trial. The improper statements were prejudicial because
they constituted a substantial part of the case, they were not
invited by Stollings, they could not be rebutted effectively, an
effective curative instruction was not given, and the weight of

2
  Ryobi then exacerbated this problem by giving an inaccurate summation
of the evidence in its closing argument. In closing, Ryobi’s counsel
reminded the jury of the newspaper article and asked rhetorically, “Why is
that significant?” To which counsel answered, “Because these are quotes
from Mr. Gass … . Mr. Gass tells us in this newspaper article—and he
doesn’t deny these quotes.” This statement was incorrect. Gass explicitly
denied that the reporter quoted him in the article. Stollings did not object
to this point during the closing argument, but by this time damage had
already been done and could not have been cured.
14                                                   No. 12-2984

the evidence was not overwhelming in Ryobi’s favor. See
Klebig, 600 F.3d at 720-21.
    To explain these factors, first, the attack on plaintiff’s
counsel was both serious and substantial. Ryobi dedicated
most of its opening statement to planting the seed in the jury’s
mind that Stollings’s counsel had a suspect motive in bringing
this case. Over half of the opening statement focused on the
intellectual property consequences of the case and the existence
of the alleged conspiratorial “joint venture” between Gass and
Stollings’s counsel. During the trial, Ryobi repeatedly drew
attention to the number of saw cases plaintiff’s counsel had
brought, referring to plaintiff’s counsel by name and even
pointing at them. In closing, Ryobi returned to the theme,
reminding the jury of the Oregonian newspaper article and
suggesting that the article explained what was really going on
in the case. This sustained focus on the motives of plaintiff’s
counsel in all phases of the trial was substantial.
    Next, the attack on counsel was not invited. The district
judge originally allowed Ryobi to make the joint venture
argument because it understood the argument to be limited to
Gass’s credibility and motives. The judge said that “the
argument that the defendant is making is certainly unusual
and not something that I in my limited experience have seen,”
but found that it “goes to Dr. Gass’s motive for testifying and
his bias.” Tr. at 1088–89. Because the plaintiff chose to use Gass
as an expert, the judge reasoned, Stollings’s counsel had to
expect Ryobi to argue that Gass was not credible. Tr. at
1091–92. If the argument had been limited to Gass’s motive for
testifying and his credibility, it would have been fair game and
we would see no error. The joint venture argument that Ryobi
No. 12-2984                                                    15

actually made went well beyond a challenge to Gass’s
credibility. Nothing in the plaintiff’s case invited an attack on
the motive of plaintiff’s counsel.
    Ryobi also argues that Stollings had an adequate
opportunity to rebut the attack and chose not to. Because
Ryobi first made the comments in its opening statement,
Stollings had an opportunity to rebut the charge during his
examination of Gass and during closing argument. By
declining not to, Ryobi suggests, Stollings concluded that the
comments were not a big deal. This argument misses the point.
We do not look to whether there was simply an opportunity to
challenge the statement to determine whether the opportunity
was adequate. Rather the opposing party must have an effective
opportunity to rebut the charge. It is hard to imagine what
Stollings could have done in this case to dispel the charge that
his lawyers were bringing an intellectual property case
masquerading as a products liability case. Once the argument
was raised, Stollings had to choose between two bad
alternatives. He could spend time addressing the argument
and risk suggesting to the jury that it was important, or he
could do his best to ignore the argument and hope the jury
focused on the elements of the case. The fact that Stollings
faced this dilemma does not mean that he had an adequate
opportunity to rebut the argument.
   Nor did the court’s instruction cure the prejudice. After
realizing that Ryobi had attacked the motives of Stollings’s
lawyers, the judge concluded that a curative instruction was
needed. The judge’s solution was to instruct the jury that the
only other similar case that was tried to a jury resulted in a
plaintiff’s verdict, but taken as a whole, the instruction was not
16                                                   No. 12-2984

effective and may well have made the situation worse. The
judge told the jury that the plaintiff’s verdict could be used for
purposes of considering “whether the other table saw cases
brought by Mr. Carpinello and Mr. Sullivan in which Dr. Gass
served as an expert witness were brought to force table saw
manufacturers to license table saw technology.’” This
instruction thus incorrectly told the jury that it could consider
the motives of Stollings’s lawyers in bringing this case, and it
did so after preventing Stollings’s lawyers from offering
additional evidence about those cases that could have taken
some of the sting out of the attack and the instruction. Under
no circumstances was counsel’s motive a proper argument for
the jury to consider. The motives of Stollings’s lawyers had no
bearing on any element of the case.
    Finally, the evidence did not so strongly favor Ryobi that
the error was harmless. Ryobi had some strong evidence: the
saw had safety features that complied with federal and
industry standards; the automatic braking technology was
expensive; and Stollings admitted that he failed to use the
safety guard, which could have prevented the accident. Yet
there was also evidence in Stollings’s favor. Ryobi’s former
chief engineer testified that he did not use the 3-in-1 guard
system on his own saw because he believed it was dangerous
when it fogged up. He also testified that he installed a riving
knife on his own saw because he believed it was safer than the
Ryobi guard. Unlike the automatic braking technology, riving
knives are both cheap and proven, and they have been widely
accepted by European regulators. And some of Stollings’s
evidence in favor of the automatic braking system had been
excluded erroneously by the court.
No. 12-2984                                                     17

    On balance, the evidence supporting the verdict was not
overwhelming, so the joint venture attack on counsel may well
have influenced the outcome of the trial. Accordingly, we find
that Ryobi’s statements about Stollings’s lawyers’ motives
deprived Stollings of a fair trial. He is entitled to a new one. We
next address the remaining issues in the appeal in the interest
of judicial economy. These issues are almost certain to arise in
a new trial. If we deferred their their resolution, we would risk
upsetting a second verdict in a subsequent appeal. We turn
now to the exclusion of plaintiff’s proposed expert testimony.
II. Exclusion of Expert Testimony
   A. Factual Background
    Stollings planned to offer expert testimony from John
Graham, a scholar who served from 2001 to 2006 as the
director of the Office of Information and Regulatory Affairs in
the federal Office of Management and Budget and is now the
dean of the Indiana University School of Public and
Environmental Affairs. Graham was to testify that including
automatic braking technology on all power saws would be
socially beneficial because the average cost of accidents per
saw that would be prevented by the technology exceeded the
cost of the braking system. Graham estimated that saws that
lack the automatic braking technology cost society an average
of $753 in accident costs over the lifetime of the average saw.
He concluded that it would therefore make economic sense to
install the technology on all saws if the cost of doing so was
less than $753 per saw. The district judge held before trial that
Graham’s testimony should be excluded under Federal Rule of
18                                                   No. 12-2984

Evidence 702 as not reliable or relevant for the trier of fact. We
conclude that this ruling was an abuse of discretion.
    Graham submitted an expert report two years before trial
laying out his opinion, methodology, supporting data, and
qualifications as required by Federal Rule of Civil Procedure
26(a)(2)(B). Graham described how he reached his conclusion
by calculating the average cost of a table saw injury (medical
costs, lost wages, pain and suffering, and litigation costs). He
then multiplied this figure by the likelihood that a saw user
would suffer an injury over the lifetime of a saw, yielding an
estimate of the societal costs of injury per table saw. He then
discounted this number by the effectiveness rate of the
automatic braking technology, which he estimated to be 90
percent. The result was an estimate of the average societal costs
of injuries per saw that occur because the technology is not
installed. The report provided the sources for all of these
inputs. Of particular relevance, Graham estimated the
effectiveness of the braking technology to be 90 percent based
on Gass’s testimony that the technology worked in the “vast
majority” of instances.
   Ryobi moved before trial to exclude his testimony for a
number of reasons, including, in passing, the reliability of the
90 percent estimate. In response to Ryobi’s motion, the district
court focused on the basis for Graham’s assumption that the
automatic braking technology was 90 percent effective at
preventing injuries. At the end of the hearing, Stollings’s
counsel received the court’s leave to make a submission “to
answer [the court’s] specific fact questions, the 90 percent and
the source of that … .”
No. 12-2984                                                   19

    Graham submitted a supplemental report ten days later
that provided a more detailed justification for the 90 percent
assumption. The new justification estimated the rates of three
common forms of failure (injuries when the saw is turned off,
injuries when the detection technology is disabled, and injuries
that occur when the operator’s hand is moving too rapidly into
the blade for the technology to activate in time). Again Graham
estimated that the technology would prevent 90 percent of
accidents.
    The court then held another hearing and decided to exclude
Graham’s testimony. This ruling was explained in an opinion
issued after trial. The court struck Graham’s supplemental
report as untimely because it was submitted one month before
trial and it was based on information that was available at the
time Graham prepared his initial report. The court noted that
when it allowed Stollings to make a submission, it should have
been limited to an explanation of how Gass’s testimony
supported the 90 percent assumption and not a new
justification for the assumption. The court then concluded that
Graham’s testimony had to be excluded under Federal Rule of
Civil Procedure 702 because the 90 percent effectiveness input
was not reliable rendered Graham’s entire opinion unreliable.
The court also agreed with a magistrate judge’s opinion in a
similar case finding that Graham’s testimony was not relevant
because the cost to society of saw accidents did not speak to the
utility of Ryobi’s specific saw design. Accordingly, the court
prohibited Graham from testifying at trial. Stollings argues that
the exclusion of the expert report was erroneous.
   B. Whether Graham’s Testimony Satisfied Rule 702
20                                                             No. 12-2984

    Expert testimony is admissible at trial under Federal Rule
of Evidence 702 if the testimony is relevant to a fact in issue, is
based on sufficient facts or data, and is the product of reliable
scientific or other expert methods that are properly applied.3
The district court is responsible for acting as a gatekeeper to
ensure that all admitted expert testimony satisfies the Rule’s
reliability and relevance requirements. See Daubert v. Merrell
Dow Pharmaceuticals, Inc., 509 U.S. 579, 592–93 (1993). But the
district court’s role as gatekeeper does not render the district
court the trier of all facts relating to expert testimony. See
Daubert, 509 U.S. at 595 (“The focus, of course, must be solely
on principles and methodology, not on the conclusions that
they generate.”); Smith v. Ford Motor Co., 215 F.3d 713, 718 (7th
Cir. 2000) (“soundness of the factual underpinnings of the
expert’s analysis and the correctness of the expert’s conclusions
based on that analysis are factual matters to be determined by
the trier of fact”). The jury must still be allowed to play its
essential role as the arbiter of the weight and credibility of
expert testimony.

3
  To be admissible, the party seeking to admit expert testimony must also
disclose the expert witness and submit a written report prepared by the
witness that contains among other things “a complete statement of all
opinions the witness will express and the basis and reasons for them” and
“the facts or data considered by the witness in forming them … .” Fed. R.
Civ. P. 26(a)(2)(B)(i)–(ii). This requirement ensures that the opposing party
has an adequate basis to examine the expert. Fed. R. Civ. P. 26 advisory
committee’s note. A party is barred from introducing evidence or testimony
that it failed to disclose without substantial justification unless the failure
was harmless. Fed. R. Civ. P. 37(c)(1). Ryobi does not argue on appeal that
the disclosure was insufficient.
No. 12-2984                                                       21

    We review a district court’s decision to exclude expert
testimony on the grounds that it is unreliable or irrelevant for
an abuse of discretion. Jenkins v. Bartlett, 487 F.3d 482, 489 (7th
Cir. 2007). We conclude here that the district judge’s decision
to exclude Graham’s testimony in this case was too great an
intrusion into the role of the jury. The testimony was both
reliable and relevant and should not have been excluded under
Rule 702.
       1. Reliability
    Expert testimony is permitted to assist the trier of fact with
technical issues that laypeople would have difficulty resolving
on their own. Expert testimony furthers this purpose only if the
expert is in fact providing the jury with genuine expertise. The
role of the judge is to ensure that the testimony the jury hears
satisfies Rule 702’s reliability requirements: that the expert is
using a valid methodology (scientific or otherwise), that there
is sufficient data to justify the use of the methodology in the
particular case, and that the expert applied the methodology
appropriately. See Fed. R. Evid. 702(b)–(d).
    Rule 702’s requirement that the district judge determine
that the expert used reliable methods does not ordinarily
extend to the reliability of the conclusions those methods
produce—that is, whether the conclusions are unimpeachable.
See Daubert, 509 U.S. at 595. An expert may provide expert
testimony based on a valid and properly applied methodology
and still offer a conclusion that is subject to doubt. It is the role
of the jury to weigh these sources of doubt. In Daubert the
Supreme Court expressly envisioned this continued role for the
jury when it reminded all that “[v]igorous cross-examination,
22                                                   No. 12-2984

presentation of contrary evidence, and careful instruction on
the burden of proof are the traditional and appropriate means
of attacking shaky but admissible evidence.” Id. at 596; see also
Walker v. Soo Line R.R. Co., 208 F.3d 581, 586–87 (7th Cir. 2000);
29 Charles Alan Wright et. al, Federal Practice and Procedure
§ 6266 (1st ed.) (observing that “where expert testimony is
based on well-established science, the courts generally have
concluded that reliability problems go to weight, not
admissibility”). As the Second Circuit has explained, trial
judges acting as gatekeepers do not assume “the role of St.
Peter at the gates of heaven, performing a searching inquiry
into the depth of an expert witness’s soul” that would
“inexorably lead to evaluating witness credibility and weight
of the evidence, the ageless role of the jury.” McCullock v. H.B.
Fuller Co., 61 F.3d 1038, 1045 (2d Cir. 1995).
    Rule 702’s reliability elements require the district judge to
determine only that the expert is providing testimony that is
based on a correct application of a reliable methodology and
that the expert considered sufficient data to employ the
methodology. For example, if an expert seeks to testify about
an average gross sales price but is going to base the testimony
on sales to only a single customer, a court would appropriately
exclude the testimony because a single observation does not
provide a sufficient basis for calculating an average. See
Wasson v. Peabody Coal Co., 542 F.3d 1172, 1176 (7th Cir. 2008)
(affirming exclusion of testimony on these facts); see also
General Electric Co. v. Joiner, 522 U.S. 136, 143–47 (1997)
(affirming exclusion of expert testimony where expert did not
provide basis for claim that studies of cancer incidence in mice
supported testimony as to cancer incidence in humans).
No. 12-2984                                                    23

    The judge should permit the jury to weigh the strength of
the expert’s conclusions, provided such shortcomings are
within the realm of a lay juror’s understanding. See Metavante
Corp. v. Emigrant Sav. Bank, 619 F.3d 748, 762 (7th Cir. 2010)
(criticism of quality of testimony goes to weight of expert
testimony, not admissibility); Smith, 215 F.3d at 718 (soundness
of factual basis and correctness of expert’s conclusions are
questions for jury). If the judge believes expert testimony is too
complex for the jury to appreciate important issues of
reliability, such that admitting the testimony would prejudice
the opposing party, the judge remains free to exclude such
evidence under Rule 403. See ATA Airlines, Inc. v. Fed. Express
Corp., 665 F.3d 882, 896 (7th Cir. 2011).
    In this case, the judge’s exclusion of Graham’s expert
testimony on reliability grounds intruded too far into the
province of the jury. The judge agreed that Graham correctly
employed a valid methodology, but the judge concluded that
Graham’s testimony was unreliable because his input for the
effectiveness of the automatic braking technology was not
sufficiently reliable. Although the 90 percent figure was
undoubtedly a rough estimate, it is also clear that Graham’s
bottom-line estimate of societal costs of saw accidents was so
high that his opinion would have remained essentially the
same even if the effectiveness rate were actually quite a bit
lower. If the effectiveness rate were 50 percent, for example,
Graham’s model would estimate the saved costs of avoided
saw accidents to society per saw to be $417—still much higher
than Ryobi’s conservative estimate of $150 to add the
technology to a saw.
24                                                 No. 12-2984

    The judge should have let the jury determine how the
uncertainty about the effectiveness rate affected the weight of
Graham’s testimony. Ryobi was free to use cross-examination
to attack the assumption and to ask Graham how altering the
assumption would affect his analysis. Graham could then have
explained that his bottom-line opinion did not depend on the
precise value for the effectiveness of the technology. Lowering
the effectiveness rate would simply lower the benefit to society
from including automatic braking on every saw, and Graham
would likely have been able to provide the jury with the full
range of alternative values. A jury should be capable of
understanding how the value of the estimate affected
Graham’s conclusions. The judge should not have excluded
Graham’s testimony on these grounds.
       2. Relevance
    Graham’s testimony also satisfied Rule 702’s relevance
requirement. Whether an issue is relevant in a case is a
question of substantive state law; whether the specific evidence
offered is relevant to resolving the issue is a procedural
question governed by the Federal Rules of Evidence. See In re
Air Crash Disaster Near Chicago, Ill. on May 25, 1979, 701 F.2d
1189, 1193 (7th Cir. 1983). As we read Illinois law, Graham’s
expert opinion is relevant to whether the Ryobi saw was
unreasonably dangerous.
    Illinois applies both the consumer expectations test and the
risk-utility test in design defect cases to determine whether a
product is unreasonably dangerous. See Mikolajczyk v. Ford
Motor Co., 901 N.E.2d 329 (Ill. 2008). If a product is
unreasonably dangerous, then the manufacturer is strictly
No. 12-2984                                                      25

liable for any injuries caused by the product. See Murphy v.
Mancari's Chrysler Plymouth, Inc., 887 N.E.2d 569, 574 (Ill. App.
2008). Under the risk-utility test, a product is unreasonably
dangerous if the risks associated with the product design
outweigh the utility of the design. In Calles v. Scripto-Tokai
Corp., 864 N.E.2d 249 (Ill. 2007), the Illinois Supreme Court
made clear that the inquiry into the risk and utility of a given
product is broad. After listing at least fourteen relevant factors
for courts to consider, including the “usefulness and
desirability of the product—its utility to the user and to the
public as a whole,” the court went on to make clear that it did
not intend the list to be exhaustive. Id. at 260-61. The relevant
considerations are many, and it is up to the fact finder to
“determine the importance of any particular factor” in each
case. Id. at 261.
    Given their approval of a broad inquiry into all aspects of
a product’s risk and utility, we believe Illinois courts would
consider the costs of a category of accidents to society a
relevant consideration in a product liability suit. This is implicit
in the court’s adoption in Calles of the factor that focuses on the
“utility to the user and to the public as a whole.” Id. at 260.
Determining utility to the public as a whole requires a
consideration of the costs the product imposes on society as
well as the benefits to society. Because the Illinois Supreme
Court has taken an inclusive view of the factors a jury may
consider, it would likely find a product’s costs to society a
relevant consideration. Graham’s testimony is relevant if it
would help the jury weigh the Ryobi saw’s costs to society.
26                                                  No. 12-2984

    Under the Federal Rules of Evidence, testimony is relevant
as long as it “has any tendency to make a fact more or less
probable” than it would otherwise be. Fed. R. Evid. 401; see
also Fed. R. Evid. 702. Graham’s testimony satisfied this liberal
relevance standard because it would have helped the jury
weigh the saw’s utility by providing the jury with a basis to
appreciate the saw’s costs to society, which is relevant under
Illinois law. See Daubert, 509 U.S. at 587 (noting liberal
relevance standard).
    Ryobi challenges this conclusion by arguing that the cost to
society is only one component of the utility of the product to
the public and is therefore too attenuated from the question of
whether the Ryobi saw’s design benefits outweigh its costs to
be relevant to an issue in dispute. Graham’s testimony, taken
alone, would not conclusively answer this ultimate question.
But expert testimony does not need to be conclusive to be
relevant. Smith, 215 F.3d at 718 (“When analyzing the relevance
of proposed testimony, the district court must consider
whether the testimony will assist the trier of fact with its
analysis of any of the issues involved in the case. The expert
need not have an opinion on the ultimate question to be
resolved by the trier of fact in order to satisfy this
requirement.”).
    Expert testimony about the average social cost of table saw
injuries over the lifetime of a saw is relevant to the jury’s
consideration of the social utility of the Ryobi saw. Graham’s
testimony would have provided the jury with a probative piece
of the evidentiary puzzle. Ryobi was free to offer other pieces
of relevant information, such as the diminished utility of the
saw caused by the addition of automatic braking technology.
No. 12-2984                                                     27

It also would have been free to expose the weaknesses in
Graham’s testimony to the jury through cross-examination.
These objections go to the testimony’s weight, not its relevance
or admissibility.
    Ryobi also objects to the relevance of Graham’s testimony
because it focused on the social cost of table saws generally, not
the Ryobi saw specifically. Graham’s testimony rests on an
assumption that the Ryobi saw is similar enough to other table
saws that the average injury rate and average cost per injury of
all saws will provide an accurate estimate for the Ryobi saw.
Perhaps this assumption makes Graham’s testimony less
powerful than if he had relied solely on an analysis of the
specific Ryobi saw model that Stollings used, but this arguable
limitation can also be addressed through cross-examination.
The fact that an expert’s testimony contains some vulnerable
assumptions does not make the testimony irrelevant or
inadmissible. Accordingly, the district court erred in
preventing Graham from testifying. The cost to society is a
relevant consideration under Illinois law, and Graham’s expert
testimony was relevant to this issue.
III.   Jury Instructions
    We turn finally to the jury instructions on unreasonably
dangerous products and proximate cause. We review de novo
whether the jury instructions stated the law correctly, but we
“afford the district court ‘substantial discretion with respect to
the precise wording of instructions so long as the final result,
read as a whole, completely and correctly states the law.’”
Lewis v. City of Chicago Police Dep’t, 590 F.3d 427, 433 (7th Cir.
2009), quoting United States v. Gibson, 530 F.3d 606, 609 (7th Cir.
28                                                   No. 12-2984

2008), and conveys the correct law “to the jury reasonably
well.” Dawson v. New York Life Ins. Co., 135 F.3d 1158, 1165 (7th
Cir. 1998). Because this is a diversity action, we look to state
law to determine whether the instruction properly stated the
substantive law; however, federal law governs whether the
instruction was sufficiently clear. See Anderson v. Griffin,
397 F.3d 515, 520 (7th Cir. 2005). We need not parse here the
distinction between substantive law and clarity because federal
and state law are in accord. As we explain below, the
unreasonably dangerous product instruction was appropriate,
but the “sole proximate cause” instruction was likely to
confuse the jury in view of Ryobi’s choice not to assert a
comparative fault defense.
     A. Unreasonably Dangerous Product Instruction
    Stollings asked the judge to give the Illinois pattern
instruction on what constitutes an unreasonably dangerous
product. The pattern instruction reads:
        When I use the expression “unreasonably
        dangerous” in these instructions, I mean unsafe
        when put to a use that is reasonably foreseeable
        considering the nature and function of the
        [product].
Illinois Pattern Instruction 400.06. The judge chose to
supplement the pattern instruction with a list of seven factors
drawn from the Calles case, instructing the jury that they “may
consider, but are not limited to” the factors. Notably for
Stollings, the list did not include a utility or cost-to-society
factor. Stollings maintains that it was error to provide the jury
No. 12-2984                                                    29

with a non-exhaustive list of factors because the list drew the
jurors’ attention to some factors at the expense of others.
     The instruction properly stated the law and was not
unreasonably confusing. The district judge employed the
Illinois pattern instruction and supplemented the instruction
with several factors that the Illinois Supreme Court approved
in its Calles decision. The judge made clear to the jury that the
factors were not exclusive and that the jurors were free to
consider other factors. This was a correct statement of the law.
It was also not confusing because we presume that jurors are
able to follow instructions, at least absent reason to believe the
instructions are ineffective. See United States v. Lee, 558 F.3d
638, 649 (7th Cir. 2009) (“Absent any showing that the jury
could not follow the court’s limiting instruction, we presume
that the jury limited its consideration of the testimony in
accordance with the court's instruction.”) (quotation omitted).
Here the judge directed the jury to several relevant factors and
made clear that these were not the only factors for the jury to
consider. We think this statement was clear enough both for
jurors to understand that they were free to consider all of the
relevant evidence and to allow counsel to argue additional
factors. This instruction was not error.
   B. Sole Proximate Cause Instruction
   Stollings also objected to the proximate cause instruction
because it contained “sole proximate cause” language. The
proximate cause instruction combined two different Illinois
pattern instructions—the pattern instruction on proximate
cause and the instruction for situations in which someone other
than the defendant may have been a cause of the injury. That
30                                                   No. 12-2984

instruction said: “If you decide that the sole proximate cause
of the plaintiff’s injury was his own conduct, then your verdict
should be for the defendant.” Tr. 2806. Stollings objected to this
instruction, arguing that it was confusing because it could be
read to invite the jury to weigh the comparative fault of Ryobi
and Stollings. Stollings favored an instruction that made clear
that Ryobi was a proximate cause if its negligence was at all
responsible for Stollings’s injury.
    The issue with the proximate cause instruction requires a
bit of background. Illinois is a modified comparative fault
jurisdiction. This means that if a plaintiff is partially
responsible for his injury, damages are reduced according to
the amount he was at fault as long as he was not more than 50
percent at fault. See 735 Ill. Comp. Stat. 5/2-1116. For example,
if the plaintiff is 30 percent responsible for his injury and the
defendant 70 percent responsible, the defendant would be
liable to the plaintiff for 70 percent of the damages. But if the
plaintiff was more than 50 percent responsible for the injury,
then the plaintiff is barred from any recovery.
    Prior to trial, Ryobi made a strategic decision to abandon
the comparative fault defense. This meant that the comparative
fault rule just described would not apply, and Stollings would
be entitled to recover all of his damages if Ryobi’s negligence
was just one proximate cause of his injury. The effect of this
decision was to force the jury to make an all-or-nothing choice:
either find Ryobi liable for all of Stollings’s damages or find
Ryobi not liable.
   The court gave the jury the following instruction on
proximate cause:
No. 12-2984                                                      31

       When I use the expression ‘proximate cause,’ I
       mean a cause that, in the natural or ordinary
       course of events, produced the plaintiff’s injury.
       It need not be the only cause nor the last or
       nearest cause. It is sufficient if it combines with
       another cause resulting in the injury. If you decide
       that the sole proximate cause of the plaintiff’s injury
       was his own conduct, then your verdict should be for
       the defendant. On the other hand, if you decide that
       the defendants’ conduct was a proximate cause of the
       plaintiff’s injury and if the plaintiff has proved the
       remaining propositions for his negligence claim or
       strict liability claim, then your verdict should be for
       the plaintiff as to that claim.
   Tr. at 2806–07 (emphasis added).
    The non-italicized text reflects the Illinois pattern
instruction on proximate cause. See IPI 15.01. The italicized text
is a variation on the pattern instruction for cases in which the
defendant argues that a third party is responsible for the
injury. See IPI 12.04. The purpose of pattern instruction 12.04
is to make clear to the jury that a negligent defendant is still
liable to the plaintiff even if a third party was also at fault for
the injury. The comments to the model instruction explain that
the “instruction should be used only where negligence of a
person who is not a party to the suit may have concurred or
contributed” to the plaintiff’s injury and “there is evidence
tending to show that the sole proximate cause of the
occurrence was the conduct of a third person.” Id. (emphasis
added). This obviously does not describe this case, in which
32                                                  No. 12-2984

Ryobi maintained that Stollings—a party to the suit—was
entirely responsible for his injury. Stollings argues that the
inclusion of the following “sole proximate cause” language
made the instruction unreasonably confusing: “If you decide
that the sole proximate cause of the plaintiff’s injury was his
own conduct, then your verdict should be for the defendant.”
    We agree with Stollings that the sole proximate cause
language was likely to cause undue confusion where no other
person’s conduct was at issue and the defendant had
abandoned a comparative fault defense. The first three
sentences, taken from the Illinois pattern instruction, correctly
explain the law on proximate cause. The objectionable “sole
proximate cause” sentence is also consistent with the law, in
the abstract, at least, if Ryobi had been trying to show that a
third party was at least partially responsible for the accident.
It is also logically correct that if Stollings was the sole
proximate cause, Ryobi would not be a proximate cause. (If
Stollings was the only proximate cause, by definition no one
else could have been a proximate cause.)
    Nevertheless, the instruction was confusing for two
reasons. First, the sole proximate cause language in the fourth
sentence would draw the jury’s attention away from the
conduct of the defendant toward the conduct of the plaintiff.
Yet there was no reason for the jury to focus on the plaintiff’s
conduct in this case because Ryobi abandoned the comparative
fault defense. Directing the jury to focus on whether the
plaintiff was the sole cause invited the jury to weigh the
respective fault of the plaintiff and the defendant and to
attempt to determine a sole cause when one may very well not
have existed. An Illinois court has warned that the sole
No. 12-2984                                                               33

proximate cause language is risky because “of its tendency to
distract the jury’s attention from the simple issues of whether
the [defendant] was negligent and whether that negligence was
the cause, in whole or in part, of the plaintiff’s injury,” Baker v.
CSX Transp., Inc., 581 N.E.2d 770, 777 (Ill. App. 1991)
(quotations omitted), and we have similarly found it error to
give the sole proximate cause instruction because it “was
bound to confuse” even though it was correct as “an abstract
proposition of law,” McCarthy v. Pennsylvania R. Co., 156 F.2d
877, 881–82 (7th Cir. 1946) (Minton, J.).4
    The second problem with the instruction is that the
evidence in the case did not suggest that there was a sole
proximate cause of Stollings’s injury. A sole proximate cause
instruction was thus likely to be particularly confusing to the
jury. See id. at 882 (cautioning against giving sole proximate
cause instruction when evidence does not suggest there was a
single proximate cause). Stollings’s legal theory was that Ryobi
was negligent (or strictly liable) for failing to include
alternative safety features on the saw because Ryobi knew that
many users did not use the 3-in-1 system. Ryobi’s response was
that it was not a cause of the injury because Stollings failed to
use the safety guard that would have prevented the injury. If
we assume for purposes of argument that Stollings’s
4
   McCarthy addressed the appropriateness of a sole proximate cause
instruction under the Federal Employers Liability Act, which holds
railroads liable to injured employees if the injury was caused in whole or
in part by the railroad’s negligence. See 45 U.S.C. § 51. Under the FELA, the
railroad is liable if its negligence is a proximate cause of the employee’s
injury regardless of whether the employee was also negligent. This case
presents a situation analogous to McCarthy, so our words of caution in that
case are equally applicable here.
34                                                   No. 12-2984

negligence or strict liability theory is correct, then Ryobi would
almost certainly also be at least a proximate cause of the injury.
It would be odd to conclude that a saw was designed
defectively due to inadequate safety features and also to
conclude that the inadequate safety features were not a
proximate cause of an injury that was made possible by the
inadequate safety features. Because it was unlikely that a jury
would find that Ryobi created a defective product but was not
a proximate cause of the injury, the sole proximate cause
instruction invited confusion here.
    Finally, if more is needed to understand that the instruction
was confusing, we need only look to Ryobi’s decision to
abandon the comparative fault defense. If Ryobi had raised the
defense of comparative fault, it would have been liable for only
the portion of Stollings’s injury for which it was responsible.
Even better for Ryobi, if Stollings was more than 50 percent
responsible for his injury, Ryobi would not be liable at all. By
forgoing the defense, Ryobi would be liable for all of Stollings’s
injury if it was merely one percent responsible for Stollings’s
injury. Why then would Ryobi forgo this defense? If the jury
correctly applied the law, Ryobi would always be better off
with the comparative fault defense. Ryobi’s strategy seems to
have depended on confusing the jury.
    The district court should not have given the sole proximate
cause instruction. Illinois Pattern Instruction 15.01 provided an
adequate statement of the law that was unlikely to confuse the
jury.
IV.    Conclusion
No. 12-2984                                                   35

     Ryobi’s improper “joint venture” theory argument aimed
at Stollings’s counsel prejudiced Stollings and deprived him of
a fair trial. Accordingly, the judgment is VACATED and the case
is REMANDED to the district court for a trial. We believe Ryobi’s
joint venture argument surprised the district judge as much as
it surprised Stollings. With hindsight the judge recognized that
the argument was improper, but at that point it was too late to
remedy the problem. We are confident, though, that Judge
Feinerman will handle this issue deftly if it arises again, so
Circuit Rule 36 shall not apply on remand.