Frequently Asked Questions about Impairment Ratings

This article is intended for RateFast users who have questions about the Whole Person Impairment ratings that come with each PR-4 Permanent & Stationary work injury report.

This FAQ contains answers to a few common questions that we’ve received regarding RateFast impairment ratings.

We pride ourselves in the accuracy of our impairment ratings, and would be happy to explain how they are being calculated. If your question isn’t answered here, then please contact us with questions about your PR-4 report.

Why is this employee’s impairment rating higher/lower than I expected it to be?

Unfortunately, in the current workers’ compensation system, there are a lot of impairment ratings that are estimated rather than rigorously calculated. In fact, we would go so far as to say that most impairment ratings circulating in the California workers’ comp system are not fully accurate, or do not take into consideration every relevant impairment factor described in the AMA Guides.

RateFast impairment ratings are derived from the data in a report—the measurements and other findings in your PR-4 (permanent and stationary) report.

As a consequence, whole person impairment values that are calculated precisely while taking into consideration the entire administrative rule set are often higher or lower than one might expect based on her/his past experience.

Whether you’re a claims adjuster, a physician, an attorney, or any other stakeholder, we encourage you to investigate the relevant chapters of the AMA Guides closely when analyzing impairment results.

For a full justification of a whole person impairment, check out the “Impairment Rating” section of your RateFast rated PR-4 report, which will include references to specific chapters and page numbers of the AMA Guides.

How does this impairment rating affect the injured worker’s disability?

Long story short, the impairment rating (which is included in every PR-4 report) is used to determine the degree of the injured worker’s disability.

A lot of people mistakenly use the terms “impairment” and “disability” interchangeably when they are, in fact, very different. The AMA Guides 5th Edition discusses the critical difference between these two concepts in Chapter 1, Philosophy, Purpose, and Appropriate Use of the Guides (Section 1.2, table 1-1 page 3). Here, you’ll find that “Impairment” is defined in the AMA Guides 5th Edition as “A loss, loss of use, or derangement of any body part, organ system, or organ function.” “Disability,” by contrast, is defined as as “An alteration of an individual’s capacity to meet personal, social, or occupational demands because of an impairment.

So, in summary, an impairment does not necessarily mean that the individual has a disability, nor does the presence of a disability always mean that an impairment is present. In California, however, the Permanent Disability Rating (which is calculated by insurance carriers or attorneys using a state-mandated formula), is dependent on the value of the Whole Person Impairment—which is the impairment rating that’s in your RateFast PR-4 report after it has been returned to you.

As you can see, there’s a lot riding on the accuracy of the impairment rating, which is why we  deliver bulletproof, fully justifiable impairment ratings to all RateFast users.

I’m a medical provider, and the insurance carrier has doubts about my RateFast impairment rating. How can you help?

Disagreements about impairment ratings often boil down to misunderstanding the AMA Guides. We will be happy to defend our ratings on your behalf. Just get in touch and explain the situation.


I’m pretty sure that the impairment rating you gave me is wrong.

We will be happy to re-review your impairment rating. If you have objections to or questions about your impairment rating, please let us know.


Why do impairment ratings seem inconsistent across different body parts?

Each body system in the AMA Guides has a different approach to rating methods. For example, take the condition of muscle atrophy. If an employee has muscle atrophy due to a work injury, then it may or may not affect the whole person impairment depending on where the muscle atrophy occurs. In the AMA Guides 5th Edition, the chapter describing the impairment rating process for shoulder, elbow, wrist and fingers (Chapter 16, “The Upper Extremities”) does not give a rating value for muscle atrophy. So, if an injury has produced muscle atrophy in the shoulder, then the impairment rating will not increase. For contrast, if an employee has muscle atrophy in the spine or in the knee as a result of the work injury, then the impairment rating will be increased (as per Chapter 15, “The Spine” and Chapter 17, “The Lower Extremities”)

As you can see, the questions, conditions, and measurements that are critical to an impairment rating change from body part to body part.

Because of this, it’s important for the evaluating physician—the person who is determining the whole person impairment—to have a firm grasp of the AMA Guides and all the factors that are relevant to calculating an impairment rating for the work injury in question, or to use an impairment rating tool such as RateFast.

Also, stakeholders need to be aware that certain combinations of injured body parts when rated in relation to one another may result in rating options not otherwise allowed when separate. In other words, an injury that affects both the spine and a lower extremity might have a different impairment rating than a separate injury to the leg and a separate injury to the spine. For example, see the thoracolumbar DRE spine provision in Chapter 15, The Spine, Table 15-4, DRE Category III, “Ongoing neurologic impairment of the lower extremity related to a thoracolumbar injury, documented by motor and sensory functions, reflexes, or findings of unilateral atrophy above or below the knee related to no other condition”.


What information was a factor in determining this impairment rating?

This changes from body part to body part, and the completeness of the PR-4 report that was submitted to RateFast. However, generally speaking, the information that you enter in the following sections can influence the impairment rating:

  • Subjective Complaints
  • Activities of Daily living
  • Objective Findings
  • Pain Assessment
  • Apportionment

The questions that RateFast asks you to complete in  PR-4 report will change depending on the body part being evaluated. This is because each injured body part has a different set of rules for rating, as per the the AMA Guides 5th Edition.

For example, Chapter 16: The Upper Extremities requires two (2) measurements be performed, as directed by the default instructions on page 20 Section 2.5d. However, when performing impairment range of motion ratings on the lower extremity, Chapter 17: The Lower Extremities requires three (3) measurements be performed as directed on page 533 Section 17.2f. Similarly, Chapter 16: The Upper Extremities requires the uninjured side serve as an impairment calculation baseline on page 453 Section 16.4c. Compare this to Chapter 17: The Lower Extremities, where no such administrative rule is present. The bottom line: RateFast will ask you different questions depending on the body parts that have been injured.


How does the Activities of Daily Living section affect impairment ratings?

In the AMA Guides 5th Edition, the Activities of Daily Living are described on page 4, Section 1.2. The Activities of Daily Living are critical because they represent the “fine tuning” and objective documentation necessary to support impairment ratings.

In the AMA Guides 5th Edition, Page 20, Section 2.5d states, “In deciding where to place an individual’s impairment rating within a range, the physician needs to consider all the criteria applicable to the condition, which includes performing the activities of daily living, and estimate the degree to which the medical impairment interferes with these activities.”

Also, it is important to understand that the Activities of Daily Living are not a measure of disability, but rather impairment.

Page 4,  Section 1.2 states, “Impairment ratings were designed to reflect functional limitation and not disability. The whole person impairment percentages listed in the Guides estimate the impact of the impairment on the individual’s overall ability to perform activities of daily living, excluding work, as listed in Table 1-2.

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