Important New Study Clarifies Science of "Minor Impact" or "MIST" Cases

Minor Impact Defense Biomechanics Dr. Michael Freeman Dr. Arthur Croft

In an important new study published this week, researchers have rejected junk science on a critical issue involved in what the insurance industry calls "minor impact" or "MIST" cases. This research addresses an issue faced by many plaintiff lawyers in trial; is the defense biomechanist or crash reconstructionist telling the truth when the testify that with smaller amounts of vehicle damage the force to the injured person is the same as the force of normal activities of daily living such as stepping off a curb, sneezing or sitting down in a chair? And can a biomechanist play any part in determining causation of injury? The short answer is that this defense has now been definitively proven as junk science, does not pass the evidentiary requirements of Daubert / Frye, and should not be admissible in any trial. Read on for the whole story.

The History of the Minor Impact Defense

The "minor impact," "minor impact soft tissue," or "MIST" defense arose in the early-1990s as the insurance industry sought ways to fight legitimate injury claims. As discussed in the legal version of From Good Hands to Boxing Gloves, McKinsey & Co. consulted with Allstate Insurance, creating Claims Core Process Redesign ("CCPR") a claim system that completely changed the auto insurance industry. One part of CCPR was fighting injury claims with minimal vehicle damage by denying injury causation or damages based upon minimal vehicle damage. This defense was advanced even though there was scientific evidence and historical evidence of injuries and even deaths in minimal vehicle damage claims.  As discussed by Dr. Michael Freeman in his chapters of the legal version of From Good Hands to Boxing GlovesMcKinsey found a company called "Minorpac" owned by two insurance defense doctors, which alleged that mathematical equations supported this contention. Unfortunately, Minorpac's equations and data were nonsensical, and did not prove what Minorpac and McKinsey claimed. This shocking background of false calculations and information demonstrates that the "minor impact" defense was always intended to intentionally underpay claims by misleading judges, jurors and even Allstate's own insurance adjustors with junk science.

Despite this, Allstate adopted the "Minor Impact Soft Tissue" or "MIST" defense in cases - either making a very lowball offer (often called "Settle for $X or Less") or simply pushed the case to trial. Allstate instituted the use of defense biomechanists and defense crash recinstructionists to support their claim that "minor damage" crashes did not injure occupants, even though the data from the US Department of Transportation's National Highway Traffic Safety Administration ("NHTSA") suggested otherwise.

The intent of the MIST defense was to make claims so expensive for plaintiffs and their lawyers that it didn't make financial sense to fight injury claims where there was little visible vehicle damage. The decision to defend these cases at any cost was to disincentivize injured people from making a claim by claiming they were greedy people faking injuries to hit the "lawsuit lottery," and disincentivizing lawyers from taking these cases by making them unreasonably expensive and financially dangerous to accept. Over time, many lawyers quit accepting claims with minimal vehicle damage, leaving injured people without legal counsel. In some cases insurers disincentivized doctors from treating these injured people by claiming that the doctor was engaging in fraud, and launching Special Investigations Unit raids in doctors offices.

Allstate reaped massive profits as a result of implementing the MIST defense, and the insurance industry followed their lead.

Bolstering the "MIST" Defense

Beyond the false calculations of Minorpac, Allstate largely based its defense of low vehicle damage car accidents on an article published by Murray Allen M.D.. Allen was a family physician in British Columbia, and at the time of the study was testifying for the Insurance Corporation of British Columbia (ICBC) in minimal damage crash injury litigation. His article on motor vehicle crashes being similar to normal activities of daily living was published in 1994 just as CCPR was being created. See Allen, M E. et al. "Acceleration Perturbations of Daily Living - A Comparison to ‘Whiplash’" Spine: June 1, 1994 - Volume 19 - Issue 11 - p 1285-1290. According to the article, "Eight volunteers were perturbed with 13 daily activities. Helmets on the heads of volunteers were instrumented with tri-planar accelerometers with output sampling of 500 Hz, sensitivity of 0.02 g, and a range of ±20 g." According to the authors, "There was wide inter-subject response for various perturbations. Plopping backward into a chair caused maximum peak acceleration horizontally at 5.6 g and vertically at 8.5 g, with force vector of 10.1 g at 54.9°. Mean impulse duration was 0.19 sec. There was no hint of injury in any subject." Allen and his co-authors concluded "Perturbations of daily living compared similarly to the jostling expected in low velocity 'whiplash' - type motor vehicle accidents." It made Allen a star in the insurance industry, resulting in him having a starring role in internal training videos for Allstate personal injury adjustors, as part of their training for handling MIST claims.

[Allen was subsequently drafted to work at the Fraser Institute, a libertarian think tank funded by tobacco companies, the Koch Family, G.D. Searle (later Monsanto), and the oil industry.]

Dismantling the MIST Defense

In 1999, the conclusions of Allen's article were refuted by leading spinal injury researchers and epidemiologists Dr. Michael FreemanDr. Arthur Croft and others. See Freeman MD, et al. A review and methodologic critique of the literature refuting whiplash syndrome. Spine. 1999 Jan 1;24(1):86-96. Plaintiff lawyers who have not read this article should do so.  

The authors note "Some authors have published articles suggesting that whiplash injuries are impossible at certain collision speeds; others have stated that the problem is psychological, or is feigned as a means to obtain secondary financial gain. These articles contradict the majority of the literature, which shows that whiplash injuries and their sequelae are a highly prevalent problem that affects a significant proportion of the population." Freeman, Croft et al identified 20 articles refuting the validity of traumatic spinal injuries, which defended the claims on nine separate bases. They then evaluated the medical, biomechanical and engineering literature related to whiplash injuries to determine if the defense articles were scientifically valid. The authors "found that all of the [defense] articles contained significant methodology flaws with regard to their respective authors' statements refuting the validity of whiplash syndrome."

Freeman & Croft note that the following are the nine categories of statements made by the defense denying causation:

  1. Acute whiplash injuries do not cause, or are unlikely to cause, chronic pain.
  2. An identifiable threshold exists and has been documented that relates velocity at impact to injury potential.  The threshold of injury is above that of vehicle damage.
  3. Specific Actions or movements common to daily living or sports and recreational activities don’t cause injury, yet involve forces similar to, or higher than, those produced in whiplash injuries.
  4. Whiplash injuries, particularly late whiplash, are less common in countries where no remuneration exists for the injuries and their long-term sequalae, or where awareness of the injury is not thought to be widespread.
  5. Symptoms commonly attributed to whiplash injuries following low-speed motor vehicle accidents, particularly chronic neck pain, are psychogenic.
  6. There is a direct correlation between the severity of impact forces and the probability of developing chronic symptoms.
  7. It is highly unlikely or impossible to injure the temporomandibular joint in a whiplash-type motor vehicle accident injury.
  8. Management of acute whiplash injuries is a contributing cause of late whiplash.
  9. The prevalence of chronic neck pain in the general population is the same as the risk of late whiplash following an acute whiplash injury.  
The article by Freeman et al. disproves each of these common insurance defenses by noting scientific methodology flaws in every one of the 20 articles supporting insurer defenses. Focusing only on the Allen study regarding activities of daily living being comparable to the forces of a car crash, Freeman et al note that Allen’s study is flawed by unsupported conclusions.  They note “Allen et al concluded that whiplash trauma and ordinary daily movements were comparable, even though none of the movements studied duplicated the vector or force of whiplash trauma.”  The articles cites that the largest published crash test to date showed peak acceleration up to six times higher than Allen.  They also note that “the duration of peak acceleration of the movements studied by Allen et al (approximately 1 millisecond) is not comparable with the duration of peak accelerations measured during whiplash trauma (70 milliseconds). Taking into account both components of acceleration (magnitude and duration), whiplash trauma produces a peak accelerative force that is more than 150 times greater than that produced by plopping in a chair.” According to the authors, this clearly misleading force information by Allen is accompanies by misleading graphics, and an inappropriate study design. [Allen's study also only considered eight people. Not great when the insurance industry denied or underpaid tens of thousands of claims based upon his purported results.]

Despite this, insurers have been successful in getting this junk science admitted into evidence. Emboldened by victories in low speed collision cases, insurance companies then started using this type of defense in cases where there is little visible vehicle damage even when there is more extensive hidden structural damage inside the car.

Biomechanist Causation Determinations Deemed Scientifically Invalid

A new article on this topic was published this week;  Nolet,P.S.;Nordhoff,L.; Kristman, V.L.; Croft, A.C.; Zeegers, M.P.; Freeman, M.D. “Is Acceleration a Valid Proxy for Injury Risk in Minimal Damage Traffic Crashes? A Comparative Review of Volunteer, ADL and Real-World Studies.” Int. J. Environ. Res. Public Health 202118, 2901.  

The authors note “Injury claims associated with minimal damage rear impact traffic crashes are often defended using a ‘biomechanical approach,’ in which the occupant forces of the crash are compared to the forces of activities of daily living (ADLs), resulting in the conclusion that the risk of injury from the crash is the same as for ADLs.” The authors state “Insurer defendants often rely on an engineering or “biomechanical approach” as a basis for denying the causal nexus between the crash and the claimed injuries.”  They go on to note “the purpose of the present investigation is to evaluate the scientific validity of the central operating premise of the biomechanical approach to injury causation; that occupant acceleration is a scientifically valid proxy for injury risk.” 

The results:

The authors note; "the results of the analyses indicated that average peak linear and angular acceleration forces observed at the head during rear impact crash tests were typically at least several times greater than average forces observed during ADLsIn contrast, the injury risk of real-world minimal damage rear impact crashes was estimated to be at least 2000 times greater than for any ADL. The results of our analysis indicate that the principle underlying the biomechanical injury causation approach, that occupant acceleration is a proxy for injury risk, is scientifically invalid. The biomechanical approach to injury causation in minimal damage crashes invariably results in the vast underestimation of the actual risk of such crashes, and should be discontinued as it is a scientifically invalid practice."

If you handle motor vehicle cases as plaintiff counsel, we suggest you read this most recent research and then challenge the admissibility of biomechanical or crash reconstruction data that challenges causation as being scientifically invalid.

Download the article.

To learn more about this research and other recent research articles supporting traumatic spinal injuries, see Dr. Freeman's on-demand CLE presentation titled "New Evidence in Low-Speed Crash Litigation: Biomechanics, Crash Reconstruction, and Causation."

Take the time to learn the medical literature involved in this field.  Dr. Arthur Croft's book Whiplash and Mild Traumatic Injuries is a good place to start, and contains extensive citations to the medical and engineering literature. You will find that the valid research confirms there is no correlation between vehicle damage and occupant injury.

For more on determining the scientific basis for injury causation, please see Dr. Michael Freeman's most recent book Forensic Epidemiology.