Are IME Examiners More Biased Than Treating Physicians?

Are IME Examiners More Biased Than Treating Physicians? What the Research Actually Shows

The assumption that treating physicians are neutral and IME examiners are biased is not supported by the evidence. The reality is more complicated, and understanding it changes how you evaluate medical opinions.

Ask almost any plaintiff attorney about independent medical examiners and you will hear some version of the same critique: the IME physician is hired by the defense or the insurer, they have a financial incentive to find against the claimant, and their opinions are predictably favorable to whoever is writing the check. Ask defense attorneys about treating physicians and you will hear the inverse: the treating physician has an ongoing relationship with the patient, they advocate for the patient's interests, and their opinions are shaped by that relationship rather than objective clinical evidence.

Both of these positions contain a grain of truth. Both are also overstatements. The research on physician bias in medicolegal settings is more nuanced than either caricature, and understanding it allows attorneys and claims professionals to evaluate medical opinions more critically on both sides.

The Case Against the 'Neutral Treating Physician' Assumption

The belief that treating physicians are the most reliable source of medical opinion because they know the patient best is one of the two faulty beliefs identified by Dr. Jennifer Christian, an occupational medicine physician, in a 2016 article published in the AMA Guides Newsletter. Christian, who led audits of over 1,400 IME and file review reports, argued that this belief reflects a misunderstanding of how the clinical relationship affects physician opinion.

Treating Physicians Are Patient Advocates, Not Neutral Evaluators

Medical training explicitly asks physicians to advocate for their patients. This is appropriate in the clinical context. The problem arises when that advocacy role bleeds into litigation. A treating physician who has been managing a patient's pain for 18 months, who has fought insurance denials on the patient's behalf, and who has developed a genuine relationship with them is not in a neutral position to render a causation opinion. Their opinion is shaped by the context in which it was formed.

Christian noted that treating physicians may provide unnecessary antibiotics, pain medications, or inappropriate treatments or even shade the truth in reports to keep patients happy. In today's environment of patient satisfaction scores and intense competition between medical groups for patients, this pressure is real and documented.

Source: Christian J. Two faulty beliefs about independent medical evaluators and impartial physicians. AMA Guides Newsletter. 2016;21(5):9-10.

Treating Physicians Work from Incomplete Information

A treating physician typically does not have access to the full medical record, prior claims history, pharmacy records, or surveillance evidence that an IME examiner reviews. They treat the patient presenting to them based on what that patient tells them and what their own examination reveals. They do not have the adversarial incentive, or the opportunity, to verify the history the patient provides.

Research reviewed by Dr. Diana Kraemer at the 2023 IAIME Annual Scientific Meeting illustrated how significant this gap can be. Studies examining patients with persistent neck and back pain after motor vehicle accidents found that approximately 50% of subjects were found, on medical record audit, to have had prior axial pain that they did not report in interview. In the group who attributed fault to another party, the medically audited rate of prior neck and back pain was more than twice the self-reported rate.

A treating physician who was not given this information, and had no reason to suspect it, formed their causation opinion on an incomplete and inaccurate history. Their opinion is not wrong because they are biased. It is wrong because the data they worked from was incomplete. The distinction matters.

The Case Against the 'Hired Gun IME Examiner' Assumption

The critique of IME examiners is that their financial relationship with the retaining party biases their opinions toward findings favorable to that party. There is legitimate concern embedded in this critique. IME examiners who are retained repeatedly by the same insurer or defense firm, and who consistently produce favorable opinions, are plausibly influenced by that relationship even without conscious awareness of it.

But the critique is often overstated, and the overstated version is routinely used to discredit legitimate IME opinions based on nothing more than the fact that they were requested by the defense or insurer.

Why Defense-Favorable Outcomes Are Expected

Christian's second faulty belief is the idea that impartial physicians should come down on the plaintiff's side and the defense's side roughly equally, a kind of parity that would signal true neutrality. She argues this is logically wrong.

Cases are not randomly selected for IME referral. They are referred by claims managers and defense attorneys who have identified something in the claim that raises a question: treatment that exceeds clinical guidelines, a causation theory that does not fit the mechanism, impairment ratings that are inconsistent with objective findings, or treatment patterns that suggest the physician is not exercising independent clinical judgment. Cases that look straightforward are rarely referred.

If claims managers are doing their jobs well, the cases they refer for IME will tend to be cases where the treating physician is, in fact, overclaiming. In that scenario, an IME examiner who comes down on the defense side more often than not is not exhibiting bias. They are accurately evaluating a pre-selected population of cases that lean in one direction to begin with.

Christian writes: 'When claims/case managers are doing a good job selecting cases for referral, we should expect that most of their decisions will favor the insurer/defense. The more expert the claims/case managers are, the more likely the independent physicians will agree because the claims/case managers are accurately detecting real problems and concerns.'

The Examinee-Reported History Problem

Dr. Robert Barth, a neuropsychologist who has written extensively on IME methodology, published a 2009 article in the AMA Guides Newsletter arguing that examinee-reported history is not a credible basis for clinical or administrative decision making. His argument is not that claimants lie, but that self-reported history in a claims context is systematically unreliable in ways that are well-documented in the research.

The problem is not limited to deliberate misrepresentation. Retrospective recall is affected by the attribution of cause (if the accident is believed to be the cause, prior symptoms are less likely to be recalled as relevant), by the litigation context, and by the way questions are framed during the clinical interview. A treating physician who takes the patient's reported history at face value and builds a causation opinion on it is building on an unreliable foundation without realizing it.

An IME examiner who independently reviews the full medical record, identifies prior treatment the claimant did not mention, and incorporates that information into their causation analysis is not being adversarial. They are applying the methodology that the research supports.

Source: Barth RJ. Examinee-reported history is not a credible basis for clinical or administrative decision making. AMA Guides Newsletter. 2009;14(5):1-7.

What 'Bias' Actually Means in This Context

Both treating physicians and IME examiners are subject to systematic biases that flow from the contexts in which they work. These biases do not make either type of physician dishonest. They make them human, operating in systems that create predictable pressures on how opinions are formed.

Treating physicians are subject to pro-patient advocacy bias, incomplete information, and the pressure of ongoing treatment relationships. IME examiners retained primarily by one side are subject to allegiance effects and the influence of repeated retention by the same referral source.

The solution is not to reject one type of opinion in favor of the other. It is to evaluate each opinion based on the quality of the examination, the completeness of record review, the rigor of the causation analysis, the examiner's qualifications in the relevant specialty, and whether the opinion engages with and explains contrary evidence.

An IME examiner who ignores prior treating records, produces a 10-page report in three days based on a 20-minute examination, and renders a causation opinion without mechanism analysis is not providing a reliable opinion, regardless of who retained them. A treating physician who accepts the patient's reported history without verification, never reviews prior imaging comparisons, and writes a causation opinion based on temporal proximity alone is not providing a reliable opinion either, regardless of their relationship with the patient.

The Standard That Applies to Both

The standard for a reliable medical causation opinion is the same whether the physician is a treating doctor or an IME examiner. The opinion must be based on a thorough examination, complete record review, a mechanism analysis that is consistent with the medical and scientific literature, and reasoning that engages with contrary evidence rather than ignoring it. It must be stated with the appropriate standard of probability and must be defensible under cross-examination.

That standard is sometimes met by treating physicians and sometimes not. It is sometimes met by IME examiners and sometimes not. Knowing which is which requires reading the opinion with the same level of critical scrutiny regardless of who wrote it.

Primary sources: Christian J., AMA Guides Newsletter 2016; Barth RJ., AMA Guides Newsletter 2009; Kraemer D., IAIME Annual Scientific Meeting 2023.

Are IME Examiners More Biased Than Treating Physicians? What the Research Actually Shows