Clear-and-Convincing Is a Standard, Not an Element: Henke v. Hospital Development of West Phoenix Recalibrates Causation Proof in Arizona Emergency-Room Malpractice

Introduction

In Henke v. Hospital Development of West Phoenix, Inc., the Arizona Supreme Court addressed a recurring and consequential question at the intersection of medical malpractice law and emergency department care: When A.R.S. § 12-572 imposes a “clear and convincing” standard of proof for malpractice claims arising from emergency-department treatment, must a plaintiff’s medical expert expressly opine that causation is “highly probable” or “reasonably certain” for the case to survive as a matter of law? Or can testimony that negligence “likely” caused the injury suffice to meet the element of causation, with the heightened standard of proof then applied by the factfinder to all the evidence?

The Court reversed summary judgment for the defendants (an emergency physician and hospital) and vacated the court of appeals’ decision, holding that § 12-572 elevates the standard of proof but does not add a new element to the claim. The plaintiff’s expert opinion that the negligence “more likely than not” caused death satisfies the prima facie element of proximate causation under § 12-563(2) and avoids impermissible speculation under Sampson v. Surgery Center of Peoria. Whether the plaintiff ultimately proves causation by “clear and convincing” evidence must be assessed from the totality of relevant, admissible evidence—not exclusively from expert testimony or expert “magic words.”

The case arises from the death of Greg Henke, who presented to urgent care with fever, chills, and malaise. Suspecting bacterial endocarditis, the urgent care physician sent him to the Abrazo West emergency department with a note and a call to the ED nurse. In the ED, he was evaluated, diagnosed with a viral syndrome, and discharged without an echocardiogram. Days later he died; autopsy showed acute bacterial endocarditis with sepsis. Plaintiff’s experts opined that, with appropriate workup and admission on March 4, Henke would “more likely than not” have survived. The trial court, and then the court of appeals, concluded those opinions failed to meet § 12-572’s clear-and-convincing burden because the experts did not speak in terms of “high probability” or “reasonable certainty.” The Supreme Court disagreed.

Summary of the Opinion

A.R.S. § 12-563 codifies the prima facie elements of medical malpractice (including proximate causation); A.R.S. § 12-572 imposes a heightened standard of proof (clear and convincing evidence) for claims arising from emergency-department care. The latter does not alter or add elements to the claim.
Expert testimony that negligence “more likely than not” or “likely” caused injury is sufficient to establish the causal connection required by § 12-563(2) so that the jury is not left to speculate about causation. A claim does not fail as a matter of law merely because an expert does not use “highly probable” language keyed to the clear-and-convincing standard.
Whether causation has been proven by clear and convincing evidence is determined from the totality of relevant, admissible evidence, including but not limited to expert testimony. Section 12-572 neither references nor requires that the heightened standard be met exclusively through expert testimony.
At summary judgment, courts may consider the applicable burden (“quantum of evidence”) under Orme School v. Reeves, but may not weigh credibility or restrict consideration to expert phrasing. If a reasonable jury could find clear and convincing proof based on all admissible evidence, summary judgment must be denied.
The Court reversed the grant of summary judgment and remanded; the separate issue concerning denial of reconsideration was rendered moot.

Analysis

Precedents Cited and Their Influence

The Court’s reasoning is firmly rooted in a careful parsing of Arizona statutes and precedent.

Statutory framework: A.R.S. §§ 12-563 and 12-572. Section 12-563(2) makes proximate causation a necessary element of malpractice; § 12-572 elevates the standard of proof to clear and convincing for emergency-department cases. The Court stresses the distinction: elements define what must be proven; standards of proof define how convinced the factfinder must be. This textual distinction anchors the holding that § 12-572 does not graft a new “high probability” element onto causation.
Beck v. Neville, 256 Ariz. 415 (2024). Beck underscores the conceptual and doctrinal separation between elements and the standard of proof. The Court invokes this separation to reject conflation of § 12-563’s elements with § 12-572’s standard of proof.
Seisinger v. Siebel, 220 Ariz. 85 (2009). Seisinger recognized that expert testimony is ordinarily necessary to establish the standard of care (and often causation) in medical malpractice, and upheld the expert-qualification statute as substantive. But Seisinger did not address § 12-572 or suggest that expert testimony is the exclusive means to satisfy a heightened standard of proof. Henke reads Seisinger for its substantive expert-testimony principle while declining to extend it into a categorical rule that only expert “high probability” wording can satisfy § 12-572.
Sampson v. Surgery Center of Peoria, 251 Ariz. 308 (2021). Sampson held that causation cannot be left to speculation; expert testimony must show that negligence probably (not possibly) caused the injury unless causation is readily apparent to a lay jury. Henke faithfully applies Sampson: the plaintiff’s “more likely than not” opinion connects the dots and avoids speculation, satisfying the causation element. Sampson does not require that the expert also speak in “highly probable” terms to match a separate standard of proof.
Saide v. Stanton, 135 Ariz. 76 (1983). Saide cautions against talismanic “magic words,” emphasizing that the trier of fact may determine probability from the evidence as a whole. Henke extends that logic to the clear-and-convincing context, rejecting a rigid insistence on “highly probable” phrasing in expert declarations at the dispositive-motion stage.
Burden-of-proof authorities: Kent K. v. Bobby M., 210 Ariz. 279 (2005); Thompson v. Better-Bilt, 171 Ariz. 550 (1992); State v. Renforth, 155 Ariz. 385 (App. 1987). These cases define and apply the clear-and-convincing standard as requiring that the asserted fact be “highly probable” or “reasonably certain,” and recognize that standards of proof calibrate the factfinder’s degree of confidence.
Summary judgment: Orme School v. Reeves, 166 Ariz. 301 (1990). Orme School allows courts to measure the sufficiency of evidence against the applicable standard of proof at summary judgment, but forbids credibility weighing and requires all reasonable inferences to be drawn for the nonmovant. Henke harmonizes this with § 12-572: courts may consider whether a reasonable jury could be clearly convinced on the whole record; they may not dismiss a case simply because an expert did not use “highly probable” wording.
Other supportive authorities. Rasor v. Northwest Hospital (expert testimony required unless causation is readily apparent) and Jamas v. Krpan (juries can evaluate the nature and gravity of deviations once informed of standards) reinforce that juries may assess the quality and force of evidence beyond formal incantations. The Court’s citation to the Revised Arizona Jury Instructions likewise illustrates that causation instructions and burden-of-proof instructions are distinct.

Legal Reasoning

The Court’s analysis proceeds in three steps.

Textual and structural interpretation. The statutes speak distinctly: § 12-563 codifies the elements; § 12-572 calibrates the standard of proof. Because the Legislature said that the “elements of proof contained in § 12-563” must be “established by clear and convincing evidence,” it elevated the factfinder’s required level of confidence in the evidence; it did not redefine the elements or demand expert testimony alone to carry the heightened burden. This tracks core evidentiary theory: standards of proof govern how sure the factfinder should be—not what must be proven.
Application to expert testimony. Under Sampson, expert causation testimony must show probability (not mere possibility) unless causation is obvious; here, the plaintiff’s experts opined “more likely than not.” That is sufficient to satisfy § 12-563(2) and prevents jury speculation. Elevating the burden under § 12-572 does not require experts to replace “probable” with “highly probable” in their phrasing; rather, the trier of fact must be ultimately persuaded to at least a “high probability” on the full evidentiary record. The Court also emphasizes that § 12-572 is silent on the type of evidence, rejecting the notion that only expert testimony can make the case “highly probable.” Other relevant, admissible evidence—provider admissions, medical records, contemporaneous communications, and the natural, unbroken sequence of events—can carry persuasive weight.
Summary judgment calibrated to the heightened burden. Courts can and should evaluate whether the record could permit a reasonable jury to find clear and convincing proof. But judges may not short-circuit that inquiry by insisting on “magic words” in expert declarations or by ignoring corroborative non-expert evidence. If a reasonable jury could be clearly convinced in light of all admissible evidence, summary judgment is improper.

The Court illustrates this through a concrete hypothetical: an emergency physician’s candid text admitting that, had she acted with more urgency, a patient “would still be alive.” That non-expert admission—combined with expert testimony establishing causal linkage to a probability—could support a clear-and-convincing finding by the jury. Suppressing such evidence in favor of a rigid “expert-only, high-probability phrasing” rule would distort § 12-572’s text and function.

Impact

Henke meaningfully reorients emergency-department malpractice litigation in Arizona without weakening the Legislature’s protective policy embodied in § 12-572.

No “magic-words” trap at the dispositive-motion stage. Plaintiffs need not elicit “highly probable” or “reasonable certainty” phrasing from causation experts to avoid summary judgment. An expert’s “more likely than not” opinion, combined with other admissible evidence, will generally suffice to send causation to the jury under the heightened standard.
The clear-and-convincing burden remains real and demanding. Plaintiffs will still need to marshal a record that could clearly convince a jury. Defendants retain robust avenues to defeat claims where the total evidence, even taken favorably to plaintiffs, cannot reasonably support a “high probability” finding (e.g., competing expert explanations, strong alternative causes, lack of temporal or pathophysiological coherence).
Broader evidentiary canvas for causation. Admissions, records, sequence-of-events evidence, and lay testimony become more salient in emergency-room malpractice—particularly where expert testimony establishes probability but the decisive move to “high probability” comes from corroboration in the non-expert proof.
Alignment with RAJI and trial practice. The decision harmonizes with the Revised Arizona Jury Instructions, which treat causation and burden separately. Trial judges should instruct on causation in the usual way and then separately instruct that the plaintiff must prove the § 12-563 elements by clear and convincing evidence when § 12-572 applies.
Summary judgment recalibrated, not eliminated. Orme School remains the touchstone: if the record, given the clear-and-convincing requirement, has “so little probative value” that no reasonable juror could find for the plaintiff, summary judgment is proper. Henke simply bars courts from granting judgment solely because an expert didn’t recite “high probability,” or by ignoring non-expert evidence bearing on causation.
Emergency medicine risk environment. The decision prevents dismissal based on semantics while preserving the Legislature’s higher proof threshold. Providers and hospitals should anticipate more cases reaching juries but should also take comfort that plaintiffs must still clear a higher evidentiary bar at trial.

Complex Concepts Simplified

Element of a claim vs. standard of proof. Elements are the building blocks of liability (e.g., breach, causation, damages). The standard of proof (e.g., preponderance, clear and convincing) is how sure the factfinder must be that each element is proven.
Preponderance of the evidence. More likely true than not (any amount over 50%).
Clear and convincing evidence. The factfinder is firmly convinced; the fact is highly probable or reasonably certain. This is a heavier burden than preponderance but lighter than “beyond a reasonable doubt.”
Proximate cause. A natural and continuous sequence of events, unbroken by an intervening cause, that produces the injury and without which the injury would not have occurred.
Role of expert testimony in medical malpractice. Because medical issues are usually beyond lay understanding, expert testimony is generally required to establish the standard of care and causation—unless causation is obvious from common knowledge.
“Magic words” fallacy. Courts do not require experts to utter precise phrases. The substance and reasoning of the opinions, together with the entire record, control.
Summary judgment with heightened burdens. Courts may consider whether the evidence could meet the higher burden as a matter of law, but cannot make credibility determinations or ignore favorable inferences and admissible corroborative evidence.
Emergency department cases and § 12-572. When care is provided in compliance with EMTALA obligations, the plaintiff must prove the § 12-563 elements by clear and convincing evidence to impose liability on the health professional and, derivatively, on the hospital.

Application to the Record

The plaintiff disclosed two causation experts. One opined that failure to evaluate for endocarditis “likely deprived [Henke] of a chance of survival,” while the cardiothoracic expert stated that if properly worked up, admitted, and treated on March 4, Henke “more likely than not” would have survived. The trial court granted summary judgment because neither expert said causation was “highly probable.” The Supreme Court held that was legal error:

The “more likely than not” opinion established the causal link required by § 12-563(2), avoiding speculation under Sampson.
Whether the plaintiff can prove causation by clear and convincing evidence must be measured by all admissible evidence, including the urgent care note and call, the ED’s rejection of that suspicion, the PCP’s post-ED assessment spotlighting endocarditis, and the autopsy confirming death from endocarditis two days later.
The Court expressed no view on whether the record ultimately meets the clear-and-convincing threshold; that question is for the factfinder (or for summary judgment only if no reasonable jury could be clearly convinced).

Practice Implications

For plaintiffs: Ensure at least one causation expert connects negligence to injury on a “more likely than not” basis to satisfy § 12-563(2). Then, build the clear-and-convincing case with corroborating admissible evidence: contemporaneous communications (including admissions), records, timeline coherence, and pathophysiology. Consider credibility, depth of reasoning, and consistency across experts and records.
For defendants: The “no high-probability phrasing, no case” strategy is no longer viable. Focus on undermining the totality of the evidence: alternative etiologies, breaks in causal sequence, lack of temporal fit, and expert credibility. Summary judgment remains available where a reasonable jury could not be clearly convinced.
For trial courts: Apply RAJI’s separate causation and burden instructions. At Rule 56, view the whole record in the light most favorable to the nonmovant; do not rely solely on expert diction; and avoid credibility weighing.
For experts: While “magic words” are not required, clarity matters. Explain the causal mechanism, address differential diagnoses, and articulate why negligence probably caused the outcome. Recognize that the jury will be instructed to reach a clear-and-convincing level of confidence, even if your professional vocabulary remains “reasonable medical probability.”

Conclusion

Henke clarifies a pivotal point in Arizona medical malpractice law: In emergency-department cases, “clear and convincing” is a standard of proof, not an element of the claim. Expert testimony that negligence “likely” or “more likely than not” caused the injury satisfies the causation element under § 12-563(2) and avoids speculation under Sampson. Whether the plaintiff ultimately reaches the “high probability” threshold is a holistic question for the factfinder, based on expert and non-expert evidence alike.

This decision forecloses dismissal based on semantic formalities and “magic words,” while preserving the Legislature’s heightened protection for emergency providers. It realigns summary-judgment practice with Arizona’s longstanding approach to burdens of proof and keeps the focus where it belongs: on whether the totality of admissible evidence can clearly convince a jury that the alleged negligence proximately caused the injury.