Causation challenges in Georgia medical malpractice

A Georgia malpractice plaintiff has to show that the negligence caused the harm, through expert opinion stated as more than a possibility. In Zwiren v. Thompson, 276 Ga. 498 (2003), the Supreme Court said the opinion must be “in terms stronger than that of medical possibility, i.e., reasonable medical probability or reasonable medical certainty”. The hard part is comparing what happened with what would have happened, in a patient who was already sick.

What Zwiren decided

Zwiren was a dispute over a jury charge. The trial court told jurors the expert had to testify “within a reasonable degree of medical certainty”. The Supreme Court held that “reasonable degree of medical certainty” is an acceptable way for an expert to express confidence, but it “is not the required standard”. It set out a charge saying that an opinion “cannot be based on speculation or possibility” and must be probable. So an expert should be asked to speak in terms of probability, and a transcript that stops at “could have” or “might have” can sink a case.

Who has to testify

A jury may not be able to decide medical causation without an expert. The expert on causation need not be the same person who addresses the standard of care. Georgia’s general admissibility rule in § 24-7-702(b) applies to all experts, and subsection (f) lets courts draw on the federal Daubert line. A court can therefore look at how the expert reached the opinion, as well as credentials. See expert disclosures and Daubert.

The comparison the expert has to make

Three questions make up the opinion:

1. What was the patient’s condition at the time of the alleged error?
2. What would proper care have been at that time, and how would the patient probably have done?
3. How does that compare with what actually happened?

The second question is the one disputed. For a late cancer diagnosis, the expert may reconstruct the likely stage at the earlier date, then compare outcomes. For a stroke or heart attack, the expert may ask whether the patient would have been a candidate for a time-limited treatment if recognized in time. Each of those steps needs a factual basis in this patient’s records, and published survival data does not answer the question for this individual by itself. Numbers from other cases or articles should not be borrowed.

Is “loss of chance” available?

A family may be told that care would have given a better chance. Zwiren states a probability standard. Two Court of Appeals decisions show the range: Dowling v. Lopez, 211 Ga. App. 578 (1993), required some showing to a reasonable degree of medical certainty that the death could have been avoided, and Richmond County Hospital Authority v. Dickerson, 182 Ga. App. 601 (1987), said proximate cause is not eliminated merely because the patient had less than a fifty percent chance of survival. Delayed diagnosis claims sets the two side by side. Neither gives a percentage rule, and anyone relying on a lost-chance theory should have counsel confirm the current law first. The safe planning assumption is that a witness has to say the negligence probably made the difference.

Other causes and other people

The defense can point to the disease itself, to another provider, or to the patient’s own conduct, and § 51-12-33 lets fault be divided among those responsible. A person’s illness is not “fault”, but it can still affect whether the negligence caused a given loss. That difference is explored on pre-existing conditions as defenses. Apportionment rules, including how fault is assigned to a non-party, are on the non-party fault page.

Causation also decides the limitation date in some cases

The two questions overlap. In Amu v. Barnes, 283 Ga. 549 (2008), a missed colon cancer was treated as a “new injury” for the limitation period, because a benign and treatable condition developed into a much more serious one, with symptoms after a symptom-free period. A plaintiff who argues that theory is making factual assertions about how the disease progressed, and those assertions have to fit the causation evidence. The article on limitation and repose has the rule.

Each item of damage needs its own link

Causation is not a single yes or no. A plaintiff may show that a delay caused an extra surgery but not that it caused a later disability. An expert should separate those points, because a verdict on one does not support the other. Under § 51-12-33(a), a plaintiff’s own share of responsibility reduces damages, and under (g) a share of 50 percent or more bars recovery.

How to pressure-test a theory before filing

Ask the proposed expert three direct questions. Would the outcome probably have been different with proper care, and how? What facts in this chart support that, as opposed to averages? What is the best explanation the defense will give, and why is it wrong? If the answer to the first is “it might have been”, the case has a causation problem, whatever the strength of the breach.

Sources

• Official Code of Georgia Annotated, November 2022 public release: §§ 24-7-702, 51-12-33
• Zwiren v. Thompson, 276 Ga. 498
• Amu v. Barnes, 283 Ga. 549

This page was last reviewed in November 2026 for general information. Laws and court decisions can change after that date. It is not legal advice and does not create an attorney-client relationship.