This sad case arises out of the 1999 suicide death of Daniel Tessier (“Tessier”), who, at the time of his death, was incarcerated at the Monroe County Detention Center (“MCDC”). Louise Cook, as Personal Representative of the Estate of Daniel F. Tessier (“Cook”), brought this action against the Sheriff of Monroe County, Rick Roth, in his official capacity, on behalf of Tessier’s estate and Jonathan Tes-sier, the minor child of Cook and Tessier. Cook alleges three bases for liability: first, she claims that the Sheriff was deliberately indifferent to Tessier’s medical needs, in violation of federal law, 42 U.S.C. § 1983; second, she says that the Sheriff is liable under Florida tort law for negligent supervision, training, and management of MCDC employees; finally, she asserts that the Sheriff is vicariously liable under Florida tort law for the negligent failure of MCDC employees to prevent Tessier’s suicide.
Cook’s case was tried in the United States District Court for the Southern District of Florida, 1 and Cook now appeals from the district court’s entry of judgment as a matter of law for the Sheriff on all counts at the close of Cook’s case. Cook also appeals the trial court’s in limine rulings excluding evidence of other suicides occurring in the MCDC, as well as the testimony of a suicide expert retained by Cook.
After careful review of the record, we affirm the trial court’s judgment for the Sheriff on Cook’s § 1983 and negligent training and supervision claims, but we conclude that the trial court erred in granting judgment as a matter of law on Cook’s vicarious liability negligence claim. We further hold that the trial court acted within its discretion in excluding evidence of other MCDC suicides and the testimony of Cook’s expert. We therefore affirm in part, reverse in part, and remand for further proceedings consistent with this opinion.
I.
The essential facts are these. Daniel Tessier was arrested for auto theft on May 18, 1999, and was subsequently processed and placed into the general population (“Unit G”) of the MCDC. The following morning, May 19, 1999, at 10:30 a.m., Tessier made a written request to see a psychiatrist, stating: “NeeD To se PHSY-CAATRISe and docToR.” Deputy Kenneth Kerr, the detention deputy assigned to Unit G that morning, testified at trial that he received and logged Tessier’s re *1101 quest, which was then placed into a box designated for medical requests. Pursuant to MCDC procedures, nurses are supposed to pick up all medical requests during their twice-daily rounds and pass them on to facility doctors. The date stamp on Tessier’s request, however, reads “May 20, 1999,” indicating that MCDC’s medical department (known as “Medical”) did not receive the request until the day after Tessier submitted it.
Deputy Kerr further testified that, when he observed Tessier on May 19, Tessier seemed nervous and appeared to be having an anxiety attack. Tessier approached Kerr later in the day complaining of chest pains, which prompted Deputy Kerr to send Tessier to Medical. Deputy Kerr did not inform Medical of Tessier’s apparent anxiety or his request to see a psychiatrist.
A nurse examined Tessier at 2:45 p.m. on May 19. Tessier complained of difficulty breathing, pain in the left side of his chest cavity, and numbness in his right hand. The nurse performed an electrocardiogram, the results of which were “borderline.” The nurse then placed Tessier on sick call, noting in his chart that the “inmate state[d] he fe[lt] better — placed on Dr. call for re-eval.” Tessier was returned to Unit G, but continued to complain of chest pains. Deputy Kerr instructed Tes-sier to lie down and told him that if “he wasn’t feeling good in a little while [Deputy Kerr] would send him back again.”
At approximately 4:00 that afternoon, May 19, Deputy Kerr received instructions to transfer Tessier to Unit A, the MCDC’s disciplinary unit, and was informed that Tessier’s phone privileges had been revoked for allegedly making harassing phone calls to witnesses. Deputy Kerr transferred Tessier into the custody of Deputy Robert Malopolski, telling him to “keep an eye on Tessier because he had been complaining of chest pains.”
Tessier was placed alone in a cell in Unit A. Deputy Malopolski observed Tessier to be nervous and anxious, and instructed him to take deep breaths and relax, and to push the intercom on the wall if he needed assistance. Deputy Malopolski thereafter responded to several intercom calls by Tessier. On one occasion, at approximately 5:00 p.m. on May 19, Deputy Malopolski found Tessier bent over on his knees on the floor of his cell, apparently having trouble breathing. Deputy Malopolski then contacted Medical, which came and took custody of Tessier.
Tessier stayed in Medical overnight, and Dr. Carol Daniels 2 treated him the following day, May 20, 1999, at 11:45 a.m. Dr. Daniels diagnosed Tessier with pleuritis, a benign condition, and ordered that Tessier be given a chest x-ray and Motrin. Tessier was discharged back to Unit A around 5:00 p.m. the same day. Deputy Malopol-ski observed that Tessier still appeared very nervous on his return.
Deputy John Whortenbury took over the night shift in Unit A at 6:00 p.m. on May 20. He was not advised that Tessier had visited Medical or that he had requested to see a psychiatrist, although he was told that Tessier had lost his phone privileges. Deputy Whortenbury observed Tessier to be “quiet, mostly polite, nervous or concerned — maybe apprehensive about being in Unit A. He had a moderate energy level, and his mannerisms and conversation gave me the impression that he was ok.”
*1102 Later that evening, at 9:20 p.m., Tessier made a second written request to see a psychiatrist, this time stating: “Need To See PHSYCATRIST AT SOON AS POSSIBLE. MeNTALY SICK, PROBLEM To BreaD.” Deputy Whortenbury testified that he asked Tessier if the request was “something that needs to be done now or can [it be] handled on the next scheduled basis,” and Tessier told him “the next scheduled time would be fine.” Deputy Whortenbury then signed Tessier’s request form and placed it in the pick-up box designated for medical requests.
At 9:35 the following morning, May 21, 1999, a deputy discovered Tessier in his cell, having hanged himself from a bedsh-eet. The last hourly check on Tessier occurred at 9:07 a.m., indicating that he had hanged himself sometime between 9:07 and 9:35. Attempts to fully revive Tessier failed, and he died two days later in the hospital when his family decided to discontinue life support.
Cook’s case against the Sheriff proceeded to trial before a jury on August 6, 2003. Cook’s witnesses included, in addition to herself and Jonathan Tessier, Deputies Kerr, Malopolski, and Whortenbury; Dr. Daniels; Dr. Tanju Mishara, Ph.D., a psychologist who treated MCDC inmates; Captain Rick Remley, the commander of detention services, who was in charge of MCDC operations at the time of Tessier’s suicide; Major Tommy Taylor, the head of the Monroe County Bureau of Corrections, which encompassed three detention facilities; and Sergeant Fernando Lopez, who was the MCDC shift sergeant at the time of Tessier’s suicide and the MCDC training sergeant at the time of trial. At no point during trial did Cook seek to introduce the testimony of her suicide expert, Dr. Maris.
The three deputies and Dr. Daniels testified primarily about their interactions with Tessier in the days and hours leading up to his suicide, as described above. Dr. Mishara commented on Tessier’s requests to see a psychiatrist, explaining that the second request, in particular, would have caused her concern as a psychologist. On cross-examination, she clarified that the May 20 request was not “an emergency situation,” and would not have been “interpret[ed] as someone who is going to be committing suicide unless there is a history or is a mental illness or depression or something like that.” Instead, the inmate “would be someone that would be on [the MCDC psychologists’] list the next time that we are there.” Dr. Mishara did say, however, that “[i]f a person came to me having written this [second request], I would certainly screen them for suicide.” In addition, Dr. Mishara described the MCDC’s procedures for processing and responding to inmate requests for psychiatric or psychological help, as well as her involvement in training deputies in suicide prevention.
Captain Remley, Major Taylor, and Sergeant Lopez further elaborated on MCDC procedures for training deputies in suicide prevention and for addressing inmate medical requests. As to the former, MCDC deputies are trained in suicide prevention, among other things, at the start of their employment, and are required thereafter to attend an annual retraining class that includes viewing a suicide prevention video.
The MCDC also maintains a written manual, the Sheriffs Policy and Procedure Manual (the “Manual”), which Cook introduced into evidence, and which includes a section on suicide prevention. The Manual contains a general statement of the MCDC’s suicide prevention policy:
It is the policy of the Monroe County Detention Facilities that all Detention Staff Members will be provided special *1103 training by qualified instructors in order to observe inmates for suicide potential during intake processing and for the identification and supervision of suicide-prone inmates during their incarceration. The suicide prevention and intervention program shall be developed[,] reviewed and approved by a qualified medical or mental health professional.
In addition, the Manual outlines screening procedures to be followed during inmate admission into the MCDC, including screening for alcohol or drug dependence, psychiatric problems, and history of suicide attempts; it enumerates a multitude of suicide risk factors and indicators; it prescribes crisis intervention techniques, explaining how to interact with a suicidal inmate and what sort of administrative and medical help to seek; and it establishes housing assignment guidelines for suicidal inmates, including suicide watch procedures.
As to inmate medical requests, requests for psychological or psychiatric help are treated in the same manner as any other medical request. The Manual contains the general policy that “[i]nmates filling out a medical request slip will be seen on the day the slip is completed or within twenty-four hours if the request is not urgent.” According to the testimony of Major Taylor, requests for psychiatric attention, like all other medical requests, are given to medical personnel, who determine whether to refer the inmate to a psychiatrist.
After two days of testimony, when Cook had called all of her witnesses, the Sheriff moved, pursuant to Federal Rule of Civil Procedure 50(a), for judgment as a matter of law on all three of Cook’s claims. The district court, ruling from the bench, granted the motion as to all claims, concluding that there had been no showing of deliberate indifference or negligent training and supervision on the part of the Sheriff, nor was the evidence sufficient to enable a reasonable person to conclude that Tessier’s suicide was foreseeable and therefore to hold the Sheriff vicariously liable for the failure of MCDC employees to prevent it. It is from this ruling, as well as from the trial court’s in limine evidentiary rulings, that Cook now appeals.
II.
We turn first to the district court’s evi-dentiary rulings on the admissibility of evidence of other suicides occurring within the MCDC and of the testimony of Cook’s suicide expert, Dr. Maris.
The legal framework against which we measure these evidentiary rulings is clear. We review a trial court’s evidentiary rulings, including its rulings on the admissibility of expert testimony, for abuse of discretion.
See, e.g., United States v. Frazier,
A.
First, Cook appeals from the district court’s order granting the Sheriffs Motion in Limine to Preclude Reference to Other Suicides. Cook sought to introduce at trial evidence oí five other suicides occurring in the MCDC within a twenty-three-month period. Three of these suicides occurred prior to Tessier’s, while two occurred af-terwards. Cook argued that the other suicides were relevant to her negligence claims “to show Defendant’s generalized business practice or habit as regards the detection and prevention of suicides in general,” and relevant to her § 1983 claim to “establish[ ] a pattern of negligence by inadequately trained/supervised personnel, such to demonstrate the Sheriffs deliberate indifference.” Plaintiffs’ Response Memorandum in Opposition to Defendant’s Motion to [sic] in Limine to Exclude Evidence of Other Suicides at 3, 6. In concert with this evidence, Cook also sought to offer testimony from her suicide expert that six suicides in twenty-three months was an excessively high rate.
The district court, however, found that the “record [was] devoid of evidence showing that the previous suicides would be relevant to Defendant’s ability to foresee the suicide of Plaintiffs’ decedent or to Defendant’s complete indifference to the decedent,” and granted the Sheriffs motion
in limine. Cook v. Roth,
We conclude that the trial court acted within its broad discretion in ruling that the evidence was not relevant.
“ ‘Relevant evidence’ means evidence having any tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it would be without the evidence.” Fed.R.Evid. 401. “Evidence of other crimes, wrongs, or acts,” while “not admissible to prove the character of a person in order to show action in conformity therewith,” “may, however, be admissible for other purposes, such as proof of motive, opportunity, in
*1105
tent, preparation, plan, knowledge, identity, or absence of mistake or accident.” Fed.R.Evid. 404(b). Such evidence is properly admitted only if it “possess[es] probative value that is not substantially outweighed by its undue prejudice.”
United States v. Jernigan,
Cook’s argument appears to be that evidence of the other suicides is admissible to demonstrate “knowledge” on the part of the Sheriff — that is, to prove, based on a pattern of suicides, that Tessier’s suicide was foreseeable. For purposes of Cook’s § 1983 claim, this argument plainly fails. Under controlling case precedent, § 1983 requires that the defendant have “notice of the suicidal tendency of
the
individual whose rights are at issue in order to be held liable for the suicide of that individual.”
Tittle v. Jefferson County Comm’n,
Whether the occurrence of five other suicides within a twenty-three month span is relevant to Cook’s negligence claims is a closer question. However, we reiterate that we review a trial court’s evidentiary rulings only for abuse of discretion, and “a district court enjoys considerable leeway in making these determinations.”
Frazier,
Cook suggests, in general terms, that the other suicides are relevant to her negligence claims because the Sheriffs awareness of the MCDC’s suicide rate illustrates that his “failure to take reasonable precautions to prevent further suicides, including that of Tessier,” was negligent. Plaintiffs’ Response Memorandum in Opposition to Defendant’s Motion to [sic] in Limine to Exclude Evidence of Other Suicides at 3. Whether a series of suicides is indeed probative of any fact material to either of Cook’s negligence claims is a debatable issue. On the one hand, the occurrence of six suicides within twenty-three months may suggest that the MCDC’s procedures for identifying and responding to suicide risks are deficient, particularly since Cook indicated that her suicide expert would testify that this suicide rate was “off the board in terms of statistical anomaly” for a facility with the population size of the MCDC. However, as the trial court observed, Cook did not establish that six suicides in twenty-three months is an unusually high rate for a facility like the MCDC — that is, a facility whose population is comparable in terms of factors such as the proportion of mentally and emotionally unstable inmates. This failure to account for all (or even many) of the factors pertinent to a facility’s suicide rate substantially diminishes, if not eviscerates, the probative value of Cook’s proffered evidence.
Moreover, as Cook conceded at oral argument, two of the other five suicides occurred after Tessier’s. Accordingly, for purposes of Cook’s claims, those two suicides surely could not have served to put the Sheriff on notice of any deficiencies in the MCDC’s procedures for detecting or addressing suicide risks. Thus, the only *1106 even potentially relevant suicides are the three occurring prior to Tessier’s.
As to those three suicides, regardless of whether they may possess some probative value, the trial court did not abuse its discretion in finding any probative value substantially outweighed by the risk of prejudice to the defendant or of misleading the jury, since the record suggests that the facts and circumstances of the other suicides differed materially from those surrounding Tessier’s. Cook offered the district court no information whatsoever regarding the facts and circumstances of the other suicides occurring within the MCDC. The Sheriff, in his motion in limine to exclude the suicides, provided minimal details about four of the five, including two of those occurring prior to Tessier’s. Inmate Larry Hounshell committed suicide on December 29, 1997, after being incarcerated for less than a day. In fact, Mr. Hounshell had not yet been booked, and committed suicide in a holding cell by hanging himself from the cord attached to a telephone in the cell. Inmate Ralph Ogden committed suicide on September 25, 1998, after being incarcerated for about two hours. Like Mr. Hounshell, Mr. Ogden had not yet been booked, and he committed suicide in a holding cell, hanging himself with his underwear.
The differences between the circumstances of Tessier’s suicide and those of these other decedents are numerous. Tes-sier had already been booked when he committed suicide; his suicide occurred on the fourth day of his incarceration; he committed suicide by hanging himself with a bedsheet; he was housed in an isolation cell within Unit A, the MCDC’s disciplinary unit, at the time of his suicide. Moreover, the record reveals that Tessier made two written requests to see a psychiatrist during his incarceration, but received no psychiatric attention before his suicide. Even comparing what precious little we know about the other MCDC suicides to Tessier’s the material differences in facts and circumstances are readily apparent.
Based on these factual differences among the suicides, and on the critical comparative facts we don’t know anything about, the trial court reasonably concluded that any probative value the other suicides might have was substantially outweighed by their potential to mislead the jury and prejudice the defendant.
See
Fed.R.Evid. 403. Thus, we conclude that the trial court did not abuse its discretion in excluding evidence of other suicides occurring within the MCDC.
Cf. Watkins v. Bowden,
B.
Cook also appeals the trial court’s decision to exclude the testimony of her proffered suicide expert, Dr. Ronald Maris, Ph.D.
Federal Rule of Evidence 702 lays out the circumstances in which expert testimony is admissible:
If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qual *1107 ified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case.
Fed.R.Evid. 702.
A trial court, in determining the admissibility of expert testimony under Rule 702, must conduct “a rigorous three-part inquiry,” considering whether
(1) the expert is qualified to testify competently regarding the matters he intends to address; (2) the methodology by which the expert reaches his conclusions is sufficiently rehable as determined by the sort of inquiry mandated in Daubert; and (3) the testimony assists the trier of fact, through the application of scientific, technical, or specialized expertise, to understand the evidence or to determine a fact in issue.
Frazier,
The proponent of the expert testimony carries a substantial burden under Rule 702. “The burden of laying the proper foundation for the admission of the expert testimony is on the party offering the expert, and admissibility must be shown by a preponderance of the evidence.”
Allison v. McGhan Med. Corp.,
In this case, the trial court did not abuse its discretion in concluding that Cook failed to carry her burden of establishing that Dr. Maris’ testimony would assist the jury, and therefore that his testimony was inadmissible under the third prong of the Rule 702 inquiry.
5
In reaching this conclusion, we reiterate that we review a trial court’s ruling on the admissibility of expert testimony only for an abuse of discretion,
see, e.g., Gen. Elec. Co. v. Joiner,
*1108 With this deferential standard in mind, we look first to the nature of the testimony Cook sought to introduce, and then to the trial court’s treatment of that evidence. Cook initially indicated her intention to introduce Dr. Maris’ testimony at the March 7, 2003 status conference, where she described Dr. Maris as “an expert in suicide prevention in correctional facilities.” Cook conceded that she had not yet filed any summary of Dr. Maris’ testimony with the trial court, but she asserted that Dr. Maris would testify about
the procedures facilities should enact as well as how they should follow procedure .... He basically is going to talk about what was wrong with the procedures and policies of the [MCDC] and the fact with a relatively small population that is a lot of suicides in a two year period and something is intrinsically wrong with the system.
The trial court expressed reservations about the appropriateness of expert testimony on these issues. The court stated:
That’s telling the jury how to rule. That may be invading the province of the jury.
If he has some knowledge not within the general understanding of the jury then an expert may be needed. I am not sure under Daubert — whether just coming in and saying we agree with the defendant, we agree with the plaintiff and here’s how you should rule.
Why can’t the lawyer argue what it is he is going to say about the procedures are not correct and not right?
As to Cook’s argument that Dr. Maris’ testimony was relevant to demonstrate that “the detention facility really should have been put on notice because they had an inordinately high rate of suicide,” the trial court told Cook:
And you can argue that to the jury. You can say, look, you don’t have to be a rocket scientist to understand if you have that kind of suicide rate you ought to look at the procedures.
The lawyers can argue that. Having a witness argue it to the jury is what I have a problem with.
The district court further observed that “[i]t may well be that we need some sort of a Daubert hearing,” but, notably, Cook never moved for such a hearing, and none was ever conducted.
Shortly thereafter, Cook filed an expert witness report, summarizing Dr. Maris’ opinions. Without elaborating on the bases for these opinions, the report laid out ten specific opinions that Dr. Maris had formed “with a reasonable degree of medical, psychological, and suicidological certainty”:
First, MCDC failed to properly assess Tessier’s suicidality, despite at least 2-3 written requests by Tessier for psychiatric treatment. MCDC’s mental health and suicide assessment forms are inadequate to detect either mental illness or impending suicide. Daniel Tessier did in fact abuse alcohol and crack cocaine and had prior suicide ideation (all known suicide risk factors) and MCDC’s assessment procedures failed to detect this.
Second, since MCDC’s own suicide prevention policies and procedures admit that most jail suicides occur with[in] the first 72 hours of incarceration, Tessier should have been put on close observation (viz., within arm’s reach 24/3) at admission. One hour checks are grossly insufficient to prevent jail hangings (which can occur in only 4 to 5 minutes; See Florida Model Jail Standards, 7.18).
Third, MCDC’s suicide prevention training proeedúres are unclear and inadequate to prevent jail suicides. All that was mentioned in the record was *1109 some available in-service suicide prevention videos.
Fourth, had Daniel Tessier seen a psychiatrist @ MCDC and been properly evaluated and treated for anxiety (e.g., given a benzodiazepine) or depression (e.g. given an SSRI antidepressant), he would more likely than not have not suicided at MCDC.
Fifth, Officer Whortenbury should have read Daniel Tessier’s 2nd written request for psychiatric treatment ... and notified the MCDC Care Center ... immediately. Two to three suicide “cries for help” were ignored by MCDC.
Sixth, MCDC had an excessive number of suicides in a two year period (viz., from 1997 to 99). The average jail suicide rate is 107/100,000 (Bonner, 1992). MCDC’s probably exceeds the average rate (I am in the process of getting inmate population numbers which will allow me to calculate that MCDC suicide rate). MCDC failed to correct, modify, or otherwise change serious suicidogenic conditions at their jail. Officer Kerr was personally involved with 3 of the MCDC suicides.
Seventh, the cells at MCDC were not suicide proofed (See Florida Model Jail Standards, 8.07).
Eighth, MCDC was deliberately indifferent to Daniel Tessier’s serious medical needs.
Ninth, MCDC violated Daniel Tessier’s constitutional right to not suffer cruel and unusual punishment, by ignoring his written requests for psychiatric treatment and evaluation.
Finally, had MCDC responded appropriately and promptly to Daniel Tes-sier’s psychiatric condition, it is more likely than not that he would not have committed suicide at the MCDC.
The Sheriff moved in limine to exclude or limit Dr. Maris’ testimony, on the grounds that it was “not legally relevant to any of Plaintiffs claims,” and that Dr. Maris’ opinion that the MCDC was deliberately indifferent to Tessier was “a legal conclusion that does little more than tell the jury what result should be reached.” Defendant Roth’s Motion in Limine to Exclude/Limit Expert Witness Testimony at 5, 2.
The court “tentatively granted” the Sheriffs motion
in limine
to exclude Dr. Maris’ testimony, providing further that “Plaintiffs may attempt to reintroduce expert testimony at trial once they have established other evidence tending to show deliberate indifference on the part of Defendant.”
6
Cook,
*1110 The record at this time is incomplete regarding the totality of the evidence to be yet presented on this issue. Plaintiffs may, or may not, meet their burden of demonstrating that the threshold (on deliberate indifference) has been met. This burden of proof must be met prior to the offering of expert testimony on screening procedures. Thus, the expert is precluded from testifying until such time as Plaintiffs present other evidence, besides inadequacies in the screening process, which give rise to a strong likelihood of deliberate indifference on the part of Defendant. 7
Id. at 1063.
Although the trial court did not say so explicitly, the concerns it expressed about Dr. Maris’ testimony in its order and the status conference (namely, whether Dr. Maris possessed any specialized knowledge not within the general understanding of the jury and whether his opinions were anything Cook’s lawyers could not just argue to the jury themselves) are best interpreted as implicating the third prong
*1111
of the Rule 702 inquiry — helpfulness to the trier of fact. “By this requirement, expert testimony is admissible if it concerns matters that are beyond the understanding of the average lay person. Proffered expert testimony generally will not help the trier of fact when it offers nothing more than what lawyers for the parties can argue in closing arguments.”
Frazier,
Moreover, “nothing in either
Dauberi
or the Federal Rules of Evidence requires a district court to admit opinion evidence which is connected to existing data only by the
ipse dixit
of the expert.”
Michigan Millers Mut. Ins. Corp. v. Benfield,
Dr. Maris’ testimony suffers from both of these defects. Some of the opinions expressed in' his report concern matters that arguably lie within the understanding of the average lay person, making expert testimony unnecessary. Others are unsubstantiated by any factual basis, so that Cook has failed to carry her burden of demonstrating that they would be helpful to the jury. In addition, much of Dr. Maris’ testimony is further lacking in any factual foundation, as required by Federal Rule of Evidence 702. See Fed.R.Evid. 702 (permitting expert testimony only if “the testimony is based upon sufficient facts or data”). Because the trial court excluded Dr. Maris’ testimony in its entirety, we evaluate each of his ten proffered opinions in turn, concluding that the trial court acted within its discretion in excluding all of them.
Dr. Maris’ first opinion — that the MCDC’s assessment procedures failed to identify Tessier’s suicidal tendencies — arguably involves no “scientific, technical, or other specialized knowledge,” Fed.R.Evid. 702, and offers nothing “beyond the understanding and experience of the average citizen,”
Rouco,
Dr. Maris’ second opinion — that Tessier should have been put on close observation, and that hourly checks are insufficient— may involve matters beyond the understanding of the average layperson. However, notably absent from this opinion are
*1112
(a) any finding that MCDC personnel should have known Tessier was suicidal, and (b) any reference to — let alone explication of — any generally accepted standard of care for dealing with suicidal inmates. Because Dr. Maris’s opinion that Tessier should have been placed under close observation is without a sufficient factual or medical foundation, again, the district court acted within its discretion in excluding it as being either unhelpful or misleading to the jury.
Cf. Frazier,
Dr. Maris’ third opinion — that the MCDC’s suicide prevention training was inadequate — is without foundation, since Dr. Maris has articulated neither a generally accepted standard for suicide prevention training in jails, nor an explanation of how or why he believes the MCDC’s training to be inadequate. Thus, this opinion “is connected to existing data only by the
ipse dixit
of the expert,”
Michigan Millers,
Dr. Maris’ fourth opinion — that had Tessier received psychiatric treatment, he probably would not have committed suicide — is similarly unsubstantiated and unspecific. It is presented without any supporting factual foundation, analysis, or explanation, and thus the trial court acted within its discretion in excluding it, too.
Dr. Maris’ fifth opinion — that Deputy Whortenbury should have read Tessier’s request for a psychiatrist and notified Medical — “offers nothing more than what lawyers for the parties can argue in closing arguments.”
Frazier,
Dr. Maris’ sixth opinion — that the MCDC’s suicide rate was disproportionately high — is, like the testimony regarding training and supervision, not relevant to any fact in issue, since the trial court excluded all evidence pertaining to other suicides occurring within the MCDC. Thus, the trial court acted within its discretion in excluding this opinion.
Dr. Maris’ seventh opinion — that the MCDC’s cells were not “suicide proofed” is indecipherable. Without any explanation of what this means or how it may be relevant, the district court acted well within its discretion in excluding this imprecise and unspecific opinion.
Dr. Maris’ eighth opinion — that MCDC “was deliberately indifferent” to Tessier’s medical needs — is another conclusion that “is connected to existing data only by the
ipse dixit
of the expert.”
Michigan Millers,
*1113 Dr. Maris’ ninth opinion- — -that the MCDC violated Tessier’s constitutional right to be free from cruel and unusual punishment — is a purely legal conclusion and is presented without any supporting factual basis. The trial court therefore acted well within its discretion in excluding it.
Dr. Maris’ final opinion — that “had MCDC responded appropriately and promptly to Daniel Tessier’s psychiatric condition,” he probably would not have committed suicide — is nearly identical to his fourth opinion, and was properly excluded for the same reasons.
In holding that the trial court did not abuse its discretion in excluding Dr. Maris’ testimony in its entirety, we stress that the burden of laying the proper foundation for the admission of expert testimony rests with its proponent.
See, e.g., Allison,
We recognize that a
Daubert
hearing before the trial court might have given Cook an additional opportunity to meet this burden, but we note that the trial court was under no obligation to hold one. As we have explained previously,
“Daubert
hearings are not required, but may be helpful in ‘complicated cases involving multiple expert witnesses.’ ”
United States v. Hansen,
Our opinion in Joiner makes clear that a court of appeals is to apply an abuse-of-discretion standard when it “review[s] a trial court’s decision to admit or exclude expert testimony.”522 U.S., at 138-139 ,118 S.Ct. 512 ,139 L.Ed.2d 508 . That standard applies as much to the trial courts decisions about how to determine reliability as to its ultimate conclusion. Otherwise, the trial judge would lack the discretionary authority needed both to avoid unnecessary “reliability” proceedings in ordinary cases where the reliability of an expert’s methods is properly taken for granted, and to require appropriate proceedings in the less usual or more complex cases where cause for questioning the expert’s reliability arises. Indeed, the Rules seek to avoid “unjustifiable expense and delay” as part of their search for “truth” and *1114 the “jus[t] determination]” of proceedings. Fed. Rule Evid. 102.
Kumho Tire Co. v. Carmichael,
Again, we stress that it was Cook’s burden — not that of the trial court — to lay the foundation for admission of Dr. Maris’ testimony; because Cook failed to do so, the district court acted within its discretion in excluding Dr. Maris’ testimony in its entirety.
III.
We turn now to the district court’s ruling, at the close of Cook’s case, on the Sheriffs motion for judgment as a matter of law on all three of Cook’s claims.
We review the district court’s grant of judgment as a matter of law
de novo,
applying the same Rule 50(a) standard that guided the trial court.
See, e.g., McCormick v. Aderholt,
“Although the existence of a genuine issue of material fact precludes judgment as a matter of law, ‘a jury question does not exist because of the presence of a “mere scintilla of evidence.” ’ ” “A motion for judgment as a matter of law will be denied only if ‘reasonable and fair-minded persons in the exercise of impartial judgment might reach different conclusions.’ ”
Mendoza,
With this standard in mind, we address in turn the trial court’s rulings on each of Cook’s three claims.
A.
First, Cook argues that deficiencies in MCDC procedures for processing and responding to inmate medical requests, as well as the Sheriffs failure to adequately train and supervise MCDC employees in suicide prevention, displayed deliberate indifference to the medical needs of suicidal detainees like Tessier, in violation of 42 U.S.C. § 1983. Section 1983 provides, in pertinent part:
Every person who, under color of any statute, ordinance, regulation, custom, or *1115 usage, of any State or Territory or the District of Columbia, subjects, or causes to be subjected, any citizen of the United States or other person within the jurisdiction thereof to the deprivation of any rights, privileges, or immunities secured by the Constitution and laws, shall be liable to the party injured in an action at law, suit in equity, or other proper proceeding for redress....
42 U.S.C. § 1983.
A § 1983 claim is predicated on an alleged violation of an underlying constitutional right. In the case of a pretrial detainee like Tessier, “the Eighth Amendment prohibitions against cruel and unusual punishment do not apply.”
Belcher v. City of Foley,
“[I]n a prisoner suicide case, to prevail under section 1983 for violation of substantive rights, under ... the ... fourteenth amendment, the plaintiff must show that the jail official displayed ‘deliberate indifference’ to the prisoner’s taking of his own life.”
Cagle,
When, as here, the defendant is the county sheriff, the suit is effectively an action against the governmental entity he represents — in this case, Monroe County.
McMillian v. Monroe County,
Thus, to succeed on her § 1983 claim, Cook must establish that the Sheriff
*1116
himself, as representative of Monroe County, was deliberately indifferent to the possibility of Tessier’s suicide, since neither respondeat superior nor vicarious liability exists under § 1983.
Belcher,
Accordingly, “our first inquiry ... is the question whether there is a direct causal link between a municipal policy or custom and the alleged constitutional deprivation.”
City of Canton,
Foreseeability, for the purpose of establishing deliberate indifference, requires that the defendant have had “subjective knowledge of a risk of serious harm,” meaning, in a prison suicide case, knowledge of “a
strong likelihood
rather than a mere possibility that the self-infliction of harm will occur.”
Cagle,
The record in this case is utterly devoid of any evidence that the Sheriff had any such knowledge. As we have explained previously, “[n]o matter how defendants’ actions might be viewed, the law of this circuit makes clear that they cannot be liable under § 1983 for the suicide of a prisoner who never had threatened or attempted suicide and who had never been considered a suicide risk.”
Tittle,
*1117
Cook argues that the MCDC’s allegedly defective procedures amount to “deliberate indifference toward a
class of suicidal detainees to which Tessier belongs,
and that the deliberate indifference toward that class caused constitutional harm to Tessier individually.” Appellant’s Br. at 29 (emphasis in original). However, as we have explained previously, under our precedent, the defendant must have had “notice of the suicidal tendency of
the
individual whose rights are at issue in order to be held liable for the suicide of that individual.”
Tittle,
Because Cook has failed to demonstrate that Tessier’s suicide was foreseeable to the Sheriff, the sole defendant in this case, “there is no legally sufficient evidentiary basis for a reasonable jury to find” deliberate indifference. Fed.R.Civ.P. 50(a). Accordingly, the district court properly entered judgment as a matter of law for the Sheriff on Cook’s § 1983 claim.
B.
Cook’s second claim is that the Sheriff is liable for Tessier’s suicide death under Florida tort law, since Tessier’s suicide was a probabfex^nd foreseeable consequence of the Sheriffs negligent failure to train and supervise MCDC employees. This claim is bkrred by Florida’s sovereign immunity law; we, therefore, conclude that the district court did not err in granting the Sheriffs motion for judgment as a matter of law on this claim as well.
As a panel of this Court has previously acknowledged, under Florida law, “a governmental agency is immune from tort liability based upon actions that involve its ‘discretionary’ functions.”
Lewis v. City of St. Petersburg,
A discretionary function, under Florida law, is one in which “the gov
*1118
ernmental act in question involved an exercise of executive or legislative power such that, for the court to intervene by way of tort law, it inappropriately would entangle itself in fundamental questions of policy and planning.”
Henderson v. Bowden,
Applying these Florida sovereign immunity principles, in
Lewis v. City of St. Petersburg,
a panel of this Court addressed a tort claim brought on behalf of the estate of a motorist shot and killed by St. Petersburg police officers, alleging that the city negligently failed to train the officers. Although, under Florida law, “an employer is liable in tort for reasonably foreseeable damages resulting from the negligent training of its employees and agents,”
Lewis,
Here, as in Lewis, the challenged actions are the Sheriffs decisions regarding “how to train its [corrections] officers and what subject matter to include in the training.” Id.; see, e.g., Appellant’s Br. at 27 (“MCDC’s suicide awareness and prevention training consists of films shown once a year.... Surely more effective methods of supervising and training detention officers were available to the Sheriff.”); id. (characterizing the issue as “[w]hether the Sheriffs methods of training and supervising personnel were reasonably effective, and whether more effective methods could have prevented Daniel Tessier’s suicide”).
Thus, as in
Lewis,
“the acts which [Cook]’s negligent training claim challenge[s] are ‘discretionary’ governmental functions immune from tort liability.”
10
Lewis,
C.
Cook’s third claim is that the Sheriff is vicariously liable, under Florida tort law, for the negligence of MCDC employees in failing to take appropriate measures to prevent Tessier’s suicide death. Because the evidence was sufficient to support a jury verdict in Cook’s favor on this claim, we reverse the district court’s grant of judgment as a matter of law for the Sheriff and remand for trial on the merits of this claim. 12
It is long established that, under Florida law, corrections officers owe individuals within their custody a duty to use reasonable care for their safety.
See, e.g., Kaisner,
*1120
Self-infliction of injury, however, is treated as an independent intervening cause, which may suffice to break the causal connection between the conduct of the corrections officer and any injury sustained by the inmate.
See, e.g., Guice v. Enfinger,
Thus, in suicide cases, Florida courts have treated as the key inquiry whether “it was reasonably foreseeable that harm would befall [the inmate] either directly or indirectly as a result of the actions and omissions of the [corrections officers].”
Overby v. Wille,
Florida’s courts have repeatedly stressed that this basic question is not one for the court to answer as a matter of law, but rather is properly left to the trier of fact for resolution.
See, e.g., Schmelz,
Indeed, under Florida law, the ev-identiary threshold for sending this claim to the jury is low.
“Only a total absence of evidence
to support an inference that the intervening cause was foreseeable justifies the court in removing the question from the trier of fact.”
Overby,
*1121 Nevertheless, without specifically acknowledging Florida law’s strong preference for a jury’s resolution of the foreseeability question, the district court found the evidence insufficient as a matter of law to support Cook’s negligence claim. The court reasoned:
The red flags that have been alluded to that the plaintiffs suggest should have alerted persons to the fact that he was a suicide risk do not rise to the level of being foreseeable.... The evidence is simply not there that there was anything that would alert a reasonable person following the established policies and procedures of the Monroe County Sheriff’s Office for the handling of inmates that would have alerted anyone to the fact that he was a suicide risk.
After thorough review of the evidence presented at trial and of the applicable Florida law, we disagree.
Four Florida cases involving negligence claims arising out of prison suicides guide our analysis. In
Guice v. Enfinger,
the First District Court of Appeals addressed the case of an inmate who was arrested while intoxicated and subsequently placed in the jail sickbay, where he apparently slept for several hours, before an employee discovered that he had hanged himself by his belt. The court concluded that “the deceased suicide was not sufficiently foreseeable to impose upon the Sheriffs employees the duty to remove the deceased’s belt,” finding “no facts in the record to indicate that the deceased had suicidal tendencies and no facts to indicate that the booking officer at the jail should have been suspicious of suicidal tendencies of the deceased.”
Guice,
However, in three subsequent cases involving prison suicides, Florida’s courts found summary judgments to have been entered erroneously, based on the existence of some evidence to support a jury finding of negligence. In
Overby v. Wille,
the decedent had flagged down a policeman and requested to be taken to a mental health facility, explaining that he thought he might have hurt someone. Instead, he was placed in jail, where he hanged himself by his belt. The Fourth District Court of Appeals concluded that the decedent’s request to be taken to the mental health facility, as well as his unprovoked violent behavior during the booking process, and the fact that jail employees labeled him a “probable Signal 20,” a designation that “refers to mental and emotional instability of some type,” constituted sufficient evidence to support a finding that his suicide was foreseeable.
See Overby,
In
Hutchinson v. Miller,
the decedent was a fifteen-year-old boy, in jail awaiting trial on a criminal charge, who was harassed, taunted, and threatened with sexual abuse by other juvenile inmates. The Fifth District Court of Appeals concluded that this treatment, “coupled with his withdrawal, his crying and his written appeals for help via his requests for transfer, all of which were known to [the sheriff and his deputies], could justify the inference that some harm to decedent was foreseeable.”
Hutchinson,
Finally, in
Schmelz v. Sheriff of Monroe County,
the Third District Court of Appeals reversed the summary disposition of a claim involving an inmate whose suicide attempt left him severely brain damaged. Although the inmate “had never either threatened, attempted, or even talked about suicide,” the booking officer ob
*1122
served him as subdued and depressed, felt “he might try to do something,” and placed him on suicide watch. In addition, the watch officer observed him as “real flustered,” nervous, and worried. Based on this “conflicting evidence as to the foreseeability of Schmelz’ actions,” the court concluded that “it was for a trier of fact to determine whether Schmelz’ own actions constituted the unforeseeable intervening cause of his injuries.”
Schmelz,
The evidence in the case before us, as in Overby, Schmelz, and Hutchinson, is “conflicting” as to foreseeability, but is sufficient to enable a jury to find that Tessier’s suicide was a reasonably foreseeable consequence of acts and omissions of MCDC employees. While Tessier never threatened or otherwise mentioned suicide, evidence presented at trial revealed that Tes-sier made two written requests to see a psychiatrist, one on each of the two days immediately preceding his suicide. And, in his second request, Tessier stated that he was “mentally sick” and asked to see a psychiatrist “as soon as possible.” In spite of these requests, Tessier was never seen by any mental health professional. Moreover, MCDC Deputies Kerr, Malopolski, and Whortenbury all observed him as being nervous and anxious. Deputy Kerr specifically observed Tessier apparently having an anxiety attack, and based on Tessier’s complaints of chest pain, Deputy Kerr sent him to Medical. Tessier’s nervous, anxious condition prompted Deputy Malopolski to instruct him to take deep breaths and relax, and to push the intercom on the wall if he needed assistance. Deputy Malopolski thereafter responded to several intercom calls by Tessier, and on one occasion found Tessier bent over on his knees on the floor of his cell, apparently having trouble breathing, after which Deputy Malopolski sent him back to Medical.
Under Florida law, these facts amount to sufficient evidence “such that reasonable people, in the exercise of impartial judgment, might reach differing conclusions” as to the
foreseeability
of Tessier’s suicide and, accordingly, the negligence of MCDC employees in failing to prevent it.
Williams v. Motorola, Inc.,
IV.
After carefully reviewing the record, we conclude that the district court erred in granting judgment as a matter of law for the Sheriff on Cook’s vicarious liability negligence claim under Florida law. However, we affirm the district court’s grant of judgment as a matter of law in favor of the Sheriff on Cook’s § 1983 claim and on her Florida law negligent training and supervision claim. We further hold that the district court acted within its discretion in excluding evidence of other suicides within the MCDC and the testimony of Cook’s *1123 proffered suicide expert. Accordingly, we reverse the district court’s judgment as a matter of law on the vicarious liability negligence claim, and affirm in all other respects.
On remand, the district court should consider whether to continue to exercise supplemental jurisdiction over Cook’s state law vicarious liability negligence claim, which is all that remains in this case. Because no basis for original federal jurisdiction presently exists, the district court has the discretion to decline to exercise supplemental jurisdiction.
See
28 U.S.C. § 1367(c) (“The district courts may decline to exercise supplemental jurisdiction over a claim ... if ... (3) the district court has dismissed all claims over which it has original jurisdiction.”);
see also, e.g., Rowe v. City of Fort Lauderdale,
AFFIRMED IN PART, REVERSED IN PART, and REMANDED.
Notes
. Cook initially sued in the Circuit Court of the Sixteenth Judicial Circuit in Monroe County, Florida, but, pursuant to the Sheriff's motion for removal under 28 U.S.C. § 1441, the case was removed to federal district court.
. Dr. Daniels, a medical doctor with a specialty in internal medicine, was employed by Prison Health Services, a company with which the Sheriff contracted to provide medical services at the MCDC.
. At the March 7, 2003 status conference, Cook indicated her intent to introduce evidence of the other suicides, and the Sheriff expressed his opposition to the admission of such evidence. To resolve the issue, the district court afforded the parties the opportunity to file memoranda of law explaining their arguments, and advised the parties that the issue was "akin to” evidence of similar acts under Federal Rule of Evidence 404(b).
. During Cook's examination of Major Taylor, the Sheriff objected on relevancy grounds to the question of whether suicide was the leading cause of death in the MCDC. After a prolonged sidebar discussion among the parties and the court, the trial court again ruled that Cook could "not go into, directly or indirectly, the other suicides.”
. Because neither the trial court nor the Sheriff expressed any reservations about Dr. Maris' qualifications or his methodology (the first two factors in the Rule 702 inquiry), and because Cook's burden is to establish all three prongs of the Rule 702 inquiry, we need not and do not consider these other two factors.
. Our review of the complete record in this case reveals that Cook never attempted to reintroduce Dr. Maris' testimony, even though the trial court explicitly gave her the opportunity to do so. Although this Circuit has not squarely addressed the issue, when a trial court rules
in limine tentatively
to exclude evidence, most courts require that the party seeking admission of the evidence offer the evidence
again
at trial in order to preserve the issue for appeal.
See, e.g., Walden v. Ga.-Pac. Corp.,
We need not consider whether to adopt this rule, however, because the trial court explicitly indicated to Cook, during trial, that her *1110 objection to the exclusion of Dr. Maris’ testimony was preserved. During a sidebar conversation on the issue of whether Cook could ask Major Taylor whether suicides were the MCDC's leading cause of death, Cook explained that "our expert that we are not going to bring down because he already has been stricken, he would have testified that statistically with an inmate population that we have in this facility ... six [suicides in twenty-three months] would have been off the board in terms of statistical anomaly.” She further stated that her expert would have testified that the MCDC's suicide rate was eight to ten times higher than average, and she observed that "[w]ithout the suicide and the nexus and without the expert of suicodology,” it would be difficult to meet the deliberate indifference standard.
The court responded: "Your record is protected on that. There is no difficulty at all in taking this to the Eleventh Circuit.” Later in the same sidebar exchange, the court stated: "It may be that [the] Appellate Court will say no, Judge King, you are wrong.... I feel very good that we have an Appellate Court that looks at all the cases and I am glad they are there because it’s a safety valve, because I do make mistakes.”
Because these comments by the trial court created the clear impression that Cook had done all she needed to do to preserve her objection to the exclusion of Dr. Maris' testimony, we cannot conclude that Cook's failure to reoffer the testimony at trial amounted to a waiver of the issue.
Cf. Thurber Corp. v. Fairchild Motor Corp.,
. We note that the trial court's tentative ruling on the admissibility of Dr. Maris' testimony focused only on the testimony's relevance to Cook’s § 1983 claim. The record makes clear, however, that Cook was offering the testimony to prove her negligence claims, as well. See, e.g., Plaintiffs’ Response Memorandum in Opposition to Defendant’s Motion to [sic] in Limine to Exclude/Limit Expert Witness Testimony at 3 (stating that Dr. Maris would testify "to the appropriate standard of care in detention facilities, the adequacy of medical and psychological care afforded inmates, and how such relates to the facts of our case”); id. at 6 ("Dr. Maris will offer testimony regarding the appropriate and governing standards of mental health care for inmates in jails and prisons instituted for the detection and prevention of suicide. Dr. Maris will explain the heightened degree of suicide risk for inmates and testify as to the reasonableness of Monroe County Detention Center policy/procedures, and the adequacy of the training, supervision and management of detention personnel.”). In reviewing the trial court’s ruling, we therefore consider whether Dr. Maris' testimony would assist the trier of fact in understanding matters related to Cook's § 1983 claim or to either of her negligence claims.
. The Sheriff urged the trial court to exclude this opinion on the ground that it was “a legal conclusion that does little more than tell the jury what result should be reached.” Defendant Roth's Motion
in Limine
to Exclude/Limit Expert Witness Testimony at 2. Although testifying experts may not offer legal conclusions, Federal Rule of Evidence 704(a) provides, in relevant part, that "testimony in the form of an opinion or inference otherwise admissible is not objectionable because it embraces an ultimate issue to be decided by the trier of fact.” Fed.R.Evid. 704(a);
see also United States v. Milton,
. Because Tessier's suicide was not foreseeable, we need not and do not consider whether the remaining elements of deliberate indifference are present here — namely, whether the County, through its policies, ‘disregarded the risk of suicide, by conduct that was more than merely negligent.
See Cagle,
. Accordingly, we note that even if the district court had abused its discretion in excluding as irrelevant Cook’s proffered evidence of other suicides occurring in the MCDC — which it did not — such an error would in no way affect Cook's negligent training and supervision claim, since sovereign immunity is a legal limitation that no amount of relevant evidence can overcome.
. The trial court granted judgment as a matter of law on the ground that Cook's evidence demonstrated that the training supplied "was sufficient.” The court "recognize[d] that [Lewis] indicate[d] that there is no duty to train per se," but did not rule on this ground, reasoning that "in a real world, logically, a sheriff in a county situation, governmental situation, would understandably feel an obligation to do training.” Because we conclude that Cook's negligent training claim is barred by Florida sovereign immunity law, we need not and do not consider whether the evidence presented could support a jury finding of negligence.
. As a preliminaiy matter, the precise scope of a sheriff's
vicarious
liability for negligence committed by jail employees is a question of Florida sovereign immunity law, which we need not address in depth, since the parties do not dispute that the Sheriff may be held vicariously liable
if
MCDC employees are found to have acted negligently. It suffices here to note that a sheriff, as "an official of a political subdivision” of the state,
Beard v. Hambrick,
.Although the Sheriff has not raised sovereign immunity as a defense to Cook's vicarious liability negligence claim, it bears noting that, under Florida law, a county’s treatment of an individual inmate in its custody is an operational function, for which the State of Florida has waived governmental immunity.
See, e.g., Henderson,
. On remand, our earlier conclusion that the district court acted within its discretion in excluding the testimony of Dr. Maris, Cook’s proffered suicide expert, should not be read to preclude Cook from re-urging Dr. Maris' testimony, nor should it be read as barring the district court from reconsidering whether Dr. Maris’ testimony might assist the trier of fact in resolving Cook’s vicarious liability negligence claim. We remind Cook that if she seeks to reintroduce Dr. Maris’ testimony, she must present it in a manner sufficiently precise, specific, and well-grounded to persuade the trial court that it would indeed assist the trier of fact.
