Impairment Rating Study

Brigham and Associates, Inc. reviews impairment evaluations nationally; the goal is to determine if ratings are accurate and the probable impairment based on the available clinical information. The Guides state on page 17 “if the clinical findings are fully described, any knowledgeable observer may check the findings with the Guides criteria”. Cases are referred by attorneys (defense and plaintiff), insurers, other claims administrators, fact finders and physicians. Many clients refer all ratings for review, whereas other clients will select ratings that they believe are questionable. It is probable that defense attorneys are more likely to refer rating reports they suspect higher than appropriate and plaintiff attorneys are more likely to refer those they suspect are lower than appropriate. It is recognized that this is not a random sample of all impairment ratings performed in the United States. It is not possible to identify which clients send all cases versus selected cases, however for those clients who state they send all reports for review, it appears the results are similar. Within these limitations, review of this data provides excellent insight to some of the challenges seen with Guides rating.

In the review process, if the original rating is judged to be incorrect by the expert reviewer and there is adequate clinical information to rate impairment, then the case is re-rated using the Guides criteria and the data provided. Each reviewing expert is a Certified Independent Medical Examiner by the American Board of Independent Medical Examiners, a Certified Impairment Rater, board-certified in occupational medicine by the American Board of Preventive Medicine, and has several years experience in clinical medicine and ratings. Therefore, typically the expert reviewer has considerable greater knowledge and skills in the use of the Guides than does the original rater. Each critique results in recording key data and preparing a written report. Although this is not a random sample, this large unique national database illustrates challenges encountered with ratings and provides unique insight to these cases.

As of December 15, 2005, 2100 cases were reviewed and entered into the database; 1445 (69%) of these were critiques of ratings that had been performed by another physician and 655 (31%) were independent ratings performed on the basis of medical records. The cases included 1103 cases reviewed in 2005, 602 in 2004 and 395 prior to 2004. Most of the cases involved the use of the Fifth Edition, this reflecting 1670 (80%) of all ratings reviewed or performed and 92% of the cases critiqued. The database was national and included workers’ compensation, Longshore and Harbor Workers Act, automobile casualty and personal injury cases. Cases from 44 different states were reviewed; 45% of the cases were from California (the Guides were adopted for use in workers’ compensation cases in 2005 as a result of workers’ compensation reform and enactment of California Senate Bill 899), 12% from Hawaii, 9% from Florida, and 37% from other states. Depending on type of case and jurisdiction the final ratings were expressed as a whole person or regional impairment.

The vast majority (98% of cases) were musculoskeletal impairment assessments, the most common being spine (36%), followed by upper extremity (31%), lower extremity (21%), and multiple musculoskeletal (12%). The most common region rated was the lumbar spine (17% of all cases).

Of the Fifth Edition cases critiqued 80% were found to be erroneous and of the Fourth Edition cases critiqued 79% were erroneous. Of the 567 California Fifth Edition cases critiqued in 2005, 78% were erroneous, and for non-California cases 84% were erroneous. Therefore the error rate seen in California with the introduction of the Guides is similar to that seen nationally; however 100% of the ratings reviewed in January-February 2005 were erroneous, this initially improved with error rates of 84% for March-April, 75% for May-June, and 73% for July-August, however then worsened with error rates increasing to 84% for September-October and to 87% for November-December. The error rate for Florida cases was a staggering 94%. The vast majority of Florida ratings were performed by treating physicians typically prior to the probable date of maximum medical improvement. Plaintiff-oriented physicians in Florida may be inclined to report permanent impairment; if no threshold injury is found, tortfeasors with personal injury protection coverage are immune from liability for most tort claims. (§627.737(1), Fla. Stat. (1995))

The error rate was higher as the value of the original rating increased; for 1037 original ratings whole person Fifth Edition ratings critiqued, for ratings under 5% whole person the error rate was 57%, between 5% and 15% whole person the error rate increased to 86%, and between 16% and 25% whole person the error rate was 94%, and over 25% the error rate was 91%. Error rates for lower extremity ratings was less (72% incorrect), than for spine (81% incorrect) and upper extremity (80% incorrect).

Each physician’s report was rated for quality on a scale of 4 – excellent, 3 – good, 2 – fair, 1 – poor and 0 – unacceptable. A rating of “good” reflects adherence to standards defined in the Guides and fair reflects adequate information to assess the case, however deficits were present. The mean scores for all physicians were: history 2.2 (fair), examination 2.1 (fair), clinical analysis 2.1 (fair), application of criteria 1.5 (between poor and fair). Comparison to criteria was consistently the weaker aspect of most reports. Review of the data suggests that rating physicians typically demonstrate consistent performance with rating, either consistently producing accurate or inaccurate ratings.

Of all the erroneous reports, 90% of the Fifth Edition ratings were higher than appeared appropriate. The corrected value for a permanent impairment rating averaged less than half of the original rating. For all Fifth Edition whole person ratings the mean original rating was 14.2% whole person permanent impairment and the mean expert rating was 6.2% whole person permanent impairment. Examining the subset of the eighty percent of Fifth Edition whole person ratings that were erroneous, the rating by the original physician averaged 15.5% (standard deviation of 9.4%) whole person permanent impairment and upon re-rating the corrected rating averaged 5.6% (standard deviation of 14.3%) whole person permanent impairment, with a correlation coefficient of 0.54.

For Fourth Edition whole person ratings the mean original rating was slightly greater at 18.4% whole person permanent impairment and the expert rating was also higher at 9.0% whole person permanent impairment. Of all Fifth Edition erroneous reports where ratable permanent impairment was originally identified, upon expert re-rating 37% were found to have no impairment; in Florida 76% previously rated as having impairment were found to have no impairment.

Examining the 839 Fifth Edition whole person erroneous ratings, 7% of the cases (61) were under-rated, i.e. based on the clinical information provided the rating should have been higher. With these cases the mean original rating was 9.9% whole person, however it should have been 16.2% whole person. Thirteen of the erroneous ratings had the same numeric value when rated, however the rating process used by the physician was incorrect and the similar results were coincidental.

Of 850 Fifth Edition cases that were found either through critique or review of records to have impairment, 90% of the cases had impairment less than 22% whole person. Less than 5% of all ratable cases have impairment greater than 30% whole person permanent impairment.

Findings for specific regions (including operative interventions) were:

For all regions the original ratings were rated higher than what appears appropriate based on the medical information provided. The error rate was consistent among regions with approximately 80% error rate, with an exception for multiple regions of the spine with the error rate being 90%. The actual mean expert rating of all regions, with the exception of thoracic spine, was between 3% and 8% whole person permanent impairment, with an overall mean of 6% whole person permanent impairment. Many of the thoracic cases involved corticospinal tract involvement and therefore were associated with greater impairment. The data suggests that are higher ratings are seen for older, male patients and for older injuries.

In summary, the analysis of the 2100 reviews reveals that the vast majority of AMA Guides ratings are erroneous and substantially higher than appropriate.