The defense oncology expert in an Atlanta delayed-diagnosis case spent the better part of his deposition explaining tumor doubling times. The plaintiff was a 58-year-old woman whose breast cancer was missed on screening mammography in March 2020 and diagnosed at Stage IIIB in November 2021. The plaintiff’s expert had testified that timely diagnosis would have identified the cancer at Stage IB or IIA, with five-year survival probability above 90 percent in either subgroup. The defense expert testified that the patient’s tumor, based on its molecular subtype and the size at actual diagnosis, would have been at most a small Stage IIB lesion at the time of the missed reading; that her actual outcome reflected the biological aggressiveness of her specific tumor; and that earlier treatment would have produced only a modest improvement in survival probability. The two experts agreed on most of the factual evidence and disagreed entirely on the counterfactual. The case turned on which counterfactual the jury believed.
Why causation is the hardest element #
The plaintiff in a Georgia medical malpractice case must prove that the defendant’s breach more likely than not caused the harm. The proof requirement applies the preponderance of the evidence standard: the plaintiff’s version of causation must be more likely than not. In many cases this is the most difficult element to establish.
The fundamental difficulty is the counterfactual problem. The plaintiff has to prove what would have happened in a world where the breach did not occur, a world that did not actually exist. The proof has to be developed through expert reconstruction of how a hypothetical correct course of care would have unfolded.
The patient was also sick before the breach. Distinguishing harm caused by the breach from harm that would have occurred regardless requires careful expert analysis. The underlying disease creates a baseline of harm that would have occurred even with non-negligent care; the breach’s contribution is the difference between the actual outcome and the counterfactual.
The defense has substantial tools for contesting causation: the natural history of the underlying disease, the limitations of available treatments, the patient’s specific characteristics that affected the response to any treatment, and other potential causes of the actual outcome. The defense expert typically constructs a counterfactual in which the same outcome occurs through the natural progression of the disease regardless of the breach.
The two components of causation #
Causation in Georgia medical malpractice has two components.
Cause in fact. The plaintiff must prove that the harm would not have occurred (or would have been substantially less severe) but for the breach. The “but for” formulation is the basic test of cause in fact.
Proximate cause. The plaintiff must prove that the harm was a foreseeable result of the breach, with no unforeseeable intervening causes breaking the chain. The proximate cause analysis filters out remote or unforeseeable consequences.
Both components must be satisfied. A breach that did not cause the harm in the but-for sense, even if it might seem related, does not produce liability. A breach that did cause the harm but produced an unforeseeable result through an intervening cause may not produce liability.
The two components operate together in practice. Most contested causation issues involve cause in fact (would the same outcome have occurred regardless?) rather than proximate cause (was the outcome foreseeable?). Proximate cause becomes the focus in cases involving unusual chains of events.
Georgia rejects pure loss-of-chance recovery #
Some jurisdictions have adopted “loss of chance” theories that allow recovery when a defendant’s negligence reduced the probability of a better outcome, even if the probability remained below 50 percent in both scenarios. Georgia has generally not adopted a pure loss-of-chance theory for medical malpractice recovery.
The implication for Georgia practice is that the plaintiff must prove the breach more likely than not caused the harm, not merely that the breach reduced the probability of a better outcome. A case where timely diagnosis would have improved survival probability from 30 percent to 60 percent may satisfy the standard (because 60 percent is more likely than not). A case where timely diagnosis would have improved survival probability from 30 percent to 45 percent may not satisfy the standard (because 45 percent is still less likely than not).
Some cases address comparable issues through different doctrinal routes. The diminution of substantial likelihood of a better outcome may support recovery in some circumstances. The specific application requires careful analysis under the controlling Georgia case law.
The practical implication is that some cases with strong evidence of breach fail at causation because the underlying disease was severe enough that the breach’s contribution to the outcome cannot be proven by a preponderance.
Cancer stage progression analysis #
Cancer cases provide perhaps the clearest example of causation analysis through counterfactual reconstruction. The analysis typically proceeds in stages.
Reconstruction of the missed diagnosis. What stage was the cancer at the time of the alleged breach? The reconstruction may use imaging from the time of the breach (if available), pathology specimens, and expert reconstruction based on the tumor’s biology and the size at actual diagnosis.
Outcome at the missed-diagnosis stage. What outcomes would have been expected if the cancer had been diagnosed at the missed-stage? Stage-specific survival statistics from large studies provide the framework. The five-year survival probability for early-stage breast cancer is generally above 90 percent; for advanced-stage disease, it is much lower.
Outcome at actual diagnosis stage. What outcomes are expected given the actual stage at diagnosis?
The difference as damages. The damages reflect the difference in expected outcomes between the missed-diagnosis stage and the actual-diagnosis stage.
The defense often contests each stage of the analysis. The tumor may have been more advanced at the missed-diagnosis point than the plaintiff’s expert reconstructs. The patient’s specific tumor biology may have produced outcomes worse than the general statistics suggest. The treatment that would have been available may not have been as effective as the plaintiff’s analysis assumes.
The dueling counterfactuals can produce wide ranges in expected damages. A plaintiff’s expert projecting Stage IA disease at the missed reading with 95 percent five-year survival has projected a substantial difference from the actual Stage IIIB outcome. A defense expert projecting Stage IIA at the missed reading with 85 percent five-year survival has projected a much smaller difference.
Acute event causation #
Causation in acute event cases (cardiac events, strokes, pulmonary emboli) involves different analysis than progressive disease causation.
The question typically is whether timely intervention would have changed the outcome. A patient with a stroke who presented within the thrombolytic window has a strong causation argument if the breach delayed recognition past the window. The thrombolytic literature provides specific evidence about the outcomes of treatment within the window versus no treatment.
A patient with a cardiac event has a strong causation argument if the breach delayed appropriate intervention (catheterization, percutaneous coronary intervention, surgical revascularization) past the point where it would have been effective. The cardiac literature provides outcomes data for various scenarios.
The defense in acute event causation often focuses on whether the patient was actually a candidate for the timely intervention. The patient’s specific medical condition may have made the intervention inappropriate or risky; the outcome may have reflected the underlying disease rather than the breach.
Multiple potential causes #
Many cases involve patients with multiple potential causes for the actual outcome. The plaintiff’s task is to establish that the breach more likely than not caused the harm, not just that it could have caused the harm.
The defense often introduces alternative causes:
Pre-existing conditions that contributed to the outcome.
Concurrent medical problems that affected the response to the actual treatment provided.
Other healthcare providers whose conduct may have contributed.
Patient non-compliance with the actual treatment provided.
The natural history of the underlying disease.
The plaintiff’s response typically involves expert analysis of the relative contributions and arguments that the breach was a substantial factor even in the presence of other potential causes. The “substantial factor” formulation can be used to address situations where multiple causes contributed; the breach can be a substantial factor without being the only cause.
The Daubert framework for expert opinions #
Expert testimony on causation in Georgia is subject to the standards under O.C.G.A. § 24-7-702 for admissibility. The court evaluates the expert’s qualifications, the reliability of the methodology, and the application to the specific case.
Defense challenges to plaintiff’s causation experts (and plaintiff challenges to defense experts) often invoke these standards. Common challenges include:
Inadequate scientific basis for the expert’s conclusions. The opinion must be grounded in scientific evidence or established medical knowledge, not speculation.
Methodology problems in how the expert reached the conclusions. The methodology should be the kind that scientists in the field would use.
Application problems in connecting the methodology to the specific case. The general principles must apply to the specific patient and circumstances.
Speculation beyond the evidence in projecting outcomes that cannot be reliably predicted.
Successful challenges to causation experts can be outcome-determinative. An expert excluded for inadequate basis or methodology problems may leave the plaintiff without admissible causation evidence, defeating the case at summary judgment.
The eggshell plaintiff doctrine #
The eggshell plaintiff doctrine modifies the causation analysis in cases involving plaintiffs with pre-existing vulnerabilities. The doctrine provides that the defendant takes the plaintiff as found, and a more vulnerable plaintiff who suffered greater harm from the same breach can recover the full extent of that harm.
The doctrine does not eliminate the causation requirement. The breach must still have caused harm; the doctrine only addresses the extent of compensable harm once causation is established.
For a plaintiff with osteoporosis whose hospital fall produced a hip fracture, the doctrine allows recovery for the hip fracture (which the fall caused) but not for the osteoporosis (which existed independently). For a plaintiff with prior brain injury whose medication error produced additional neurological injury, the doctrine allows recovery for the additional injury but not for the prior baseline impairment.
Causation in damages, not just liability #
Causation operates not only at the liability stage but throughout the damages analysis. Each item of claimed damages must be causally connected to the breach.
The plaintiff with a serious surgical complication may have damages from the complication itself, from the additional surgeries to address it, from the lost work during recovery, from the ongoing care needs. Each must be tied to the breach rather than to other potential causes.
The defense often contests individual damages categories on causation grounds. Specific medical costs may be argued to reflect the underlying condition rather than the breach. Specific functional limitations may be argued to reflect pre-existing impairments. Specific lost earnings may be argued to reflect employment changes unrelated to the injury.
The causation analysis is case-specific #
A delayed-diagnosis case for an Atlanta breast cancer patient may turn on whether timely diagnosis at Stage IB would have produced a 95 percent five-year survival or at Stage IIB would have produced an 85 percent survival, against the actual 50 percent five-year survival at Stage IIIB. A missed-stroke case for a Macon patient who presented at hour two may turn on whether the missed window prevented thrombolysis that would have produced a substantially better outcome. A surgical complication case for a Savannah cholecystectomy patient may turn on whether the bile duct injury would have occurred even with optimal technique. The counterfactual the jury accepts decides whether the damages reflect the breach’s contribution or the natural history of the disease. The expert preparation on causation is often the most consequential preparation in the case.
This article is for informational purposes only and does not constitute legal advice. Personal injury cases turn on specific facts and applicable law that vary by case. If you have been injured in Georgia and want to understand your legal options, consult a licensed Georgia personal injury attorney.