Whole Person Impairment Ratings: The AMA Guides, ADLs, and Almaraz/Guzman
Short answer: whole person impairment is a percentage describing how much a permanent medical condition reduces a person's ability to carry out activities of daily living, rated under the AMA Guides to the Evaluation of Permanent Impairment, 5th Edition, which California adopted for injuries on or after January 1, 2005. Impairment is a medical finding. Disability is what the system does with it. And because the Guides define impairment in terms of ADL impact, a rating with no documented ADL assessment is a rating with no foundation.
Impairment and disability are not the same thing
The AMA Guides define impairment as a loss, loss of use, or derangement of any body part, organ system, or organ function. That is a medical determination, and it is the QME's job.
Disability is different. The Guides describe it as an alteration of an individual's capacity to meet personal, social, or occupational demands because of an impairment. California narrows this further. In the DWC's 2016 Physician's Guide, disability is a condition that interferes with the ability to work or causes lost time from work. The cleanest working definition in the California system is lost compensable work: wages not earned. A worker on modified duty or restrictions has a partial version of the same thing.
That distinction has a consequence most physicians miss on first contact with this system. A condition that causes no lost work time, no interference with the ability to work, and no need for medical treatment is not an injury as the workers' compensation system uses the word, however real it is clinically.
For payment, Labor Code §4660 (for older injuries) and §4660.1 (for injuries on or after January 1, 2013) frame permanent disability in terms of diminished future earning capacity. The system is compensating the narrowing of what a person can earn for the rest of their working life. A worker with an amputation can accept a smaller set of jobs; the award is meant to bridge the gap between what they can now earn and what they could have.
How a rating gets made
For injuries on or after January 1, 2005, the Permanent Disability Rating Schedule uses the AMA Guides 5th Edition as the starting point, then accounts for the nature of the physical injury or disfigurement, the worker's occupation, and their age at the time of injury.
Of those three inputs, two are essentially factual and rarely disputed. Age is a fact. Occupation is occasionally argued over classification but is usually settled. The nature of the physical injury is the disputed one, and it is the one the QME supplies. That is where the evaluator sits in the machinery.
Activities of daily living are the foundation, not a formality
The Guides assess an impairment by its impact on activities of daily living. Table 1.2 lists the categories: self-care and personal hygiene, communication, physical activity, sensory function, non-specialized hand activities, travel, sexual function, and sleep.
Stick to those categories. They are what the Guides rate against, and a rating that cites them is defensible in a way that improvised categories are not.
This is the part that gets short-changed. California's own Physician's Guide barely mentions ADLs, referring to them only where pain interferes with activity, so an evaluator working from the California documents alone can produce a report with no meaningful ADL section. The AMA Guides are built on ADLs. The entire concept of permanent impairment in the 5th Edition rests on them.
Practically, that means the ADL assessment in a face-to-face evaluation is as important as the physical examination, and deserves as much space in the report. How to take one, category by category, is its own post. A structured questionnaire plus specific questioning about each category, documented, is what supports the number you eventually produce.
Rate every impairment, not just the obvious one
A rating should account for all impairments from the illness or injury and from its treatment, not only the primary body part or organ system.
A community college welding instructor yanks on a stuck door and injures his wrist. He has surgery: a resection of the distal ulna with fusion hardware through the distal radius. That wrist is the primary region. But eight weeks in a cast leaves him, six months later, unable to fully extend the elbow, and with stiffness and incomplete extension in the fingers. Those are secondary, they are consequences of the treatment, and they are ratable.
Omit one and the applicant's attorney will be back asking you to reconsider, which costs everyone a supplemental report.
The DWC's own study guide works through the same principle using cancer, where the Guides provide no direct rating for the disease itself. A breast cancer evaluation should consider not only mastectomy, lumpectomy, or lymph node surgery, but loss of upper extremity function, skin disfigurement and scarring, and impairment from chemotherapy including premature menopause, loss of ovarian function, and peripheral neuropathy, plus effects of radiation and long-term medication. The complete evaluation delineates every factor, assigns whole person impairment to each, and cites the supporting section or table.
Under the Guides, a mastectomy in a woman outside childbearing age rates at zero percent whole person impairment, because the Guides treat breast function as lactation. Litigation over exactly that outcome is part of why the DWC guidance now emphasizes rating the full impact of a condition and its treatment rather than the headline body part.
Rating unlisted conditions by analogy
The Guides cannot describe every condition, and examinees turn up with conditions that are simply not in the book. The instruction for those cases is to use clinical judgment, comparing measurable impairment from the unlisted condition to measurable impairment from similar listed conditions.
A worked example: an examinee develops internal coxa saltans, snapping hip, with pain, clicking, and an effect on gait. Coxa saltans appears nowhere in the Guides. Trochanteric bursitis does, and it produces pain around the hip and difficulty walking when flared. Rating the snapping hip by analogy to trochanteric bursitis is legitimate, because the conditions are analogous in measurable impairment and in ADL impact.
The analogy has to be defended on those grounds. Similar impairment, similar limitation in activities of daily living, stated with reasons.
The four corners rule: Almaraz/Guzman
The rating produced by the schedule is prima facie evidence of the percentage of disability. It is presumed correct, and it is rebuttable.
In consolidated en banc decisions in Almaraz v. SCIF and Guzman v. Milpitas Unified School District, the Appeals Board held first, in February 2009, that the AMA Guides portion of the rating schedule is rebuttable, and then, in September 2009, that a party may rebut a scheduled rating by challenging a component of it, including the whole person impairment. The Board added the limit that gives the doctrine its name: all impairment evidence must come from within the four corners of the AMA Guides, though the physician may use any chapter, table, or method in the Guides. The Court of Appeal affirmed in Milpitas Unified School District v. WCAB (Guzman) (2010) 187 Cal.App.4th 808.
What this means at the desk is that you are not locked into the obvious chapter. Use the chapter, table, or method that most accurately reflects the examinee's impairment, and say why.
A low back injury is normally rated from Chapter 15. But if the impairment principally shows up as a derangement of gait, the lower extremity chapter may capture it more accurately. If it shows up as a loss of lifting capacity, another chapter may. Judgment, experience, and training decide which, and the standard is accuracy, not advantage.
Two cautions. First, the Guides tend to produce conservative numbers, which is why applicant attorneys welcomed the flexibility; but "more accurate" is the test, not "higher." Second, a rebuttal is a rating like any other and has to be reasoned. An Almaraz/Guzman rating with no explanation of why the alternative method is more accurate is a conclusory opinion in a more elaborate costume.
Where this connects to the rest of the report
A rating drives the apportionment section, and how you characterize the impairment can determine whether a pre-existing condition contributes to it. That is covered in the apportionment post. The rating also has to appear in a report section that explains the criteria used, the rating itself, and the calculation, which is part of the required elements.
And all of it rests on the record. Prior imaging, previous ratings, earlier restrictions, and pre-injury complaints determine both what is ratable and what is apportionable. Lexamed reads the full production and returns a page-cited chronology with those findings flagged, so the rating and the apportionment underneath it are built on evidence you can point to.
Frequently asked questions
What is whole person impairment? A percentage describing how much a permanent medical condition reduces a person's ability to perform activities of daily living, rated under the AMA Guides to the Evaluation of Permanent Impairment, 5th Edition. It is a medical finding, distinct from disability.
What is the difference between impairment and disability? Impairment is a loss, loss of use, or derangement of a body part, organ system, or organ function, and it is a medical determination. Disability is the effect on a person's capacity to meet demands, and in California workers' compensation it centers on the ability to work and on diminished future earning capacity.
How do activities of daily living affect an impairment rating? The AMA Guides define impairment by its impact on activities of daily living, using the categories in Table 1.2: self-care, communication, physical activity, sensory function, hand activities, travel, sexual function, and sleep. A rating without a documented ADL assessment lacks the foundation the Guides require.
How does a QME rate a condition that is not in the AMA Guides? By analogy. The evaluator compares measurable impairment from the unlisted condition to measurable impairment from a listed condition with similar limitations, and explains why the two are analogous.
What is the Almaraz/Guzman four corners rule? The Appeals Board held in 2009 that a scheduled permanent disability rating is rebuttable and that impairment evidence must come from within the four corners of the AMA Guides, while permitting a physician to use any chapter, table, or method in the Guides that most accurately reflects the impairment. The Court of Appeal affirmed in 2010.
Should a QME rate secondary body parts affected by treatment? Yes. The rating should account for all impairments from the injury and from its treatment, not only the primary body part, including consequences such as loss of motion in adjacent joints after immobilization.
Is the AMA Guides rating final? It is prima facie evidence, meaning presumed correct but rebuttable. A party may challenge a component of the rating, and a physician may support a different rating using another method within the Guides, provided the reasoning is stated.