California permanent disability ratings explained: WPI, the 2005 PDRS and apportionment

A permanent disability (PD) rating turns a doctor's impairment findings into a percentage, and the percentage into weeks of payments. Applicant attorneys don't have to rate every report by hand, but they do need to read a rating string, spot what moved it and know which rules apply to the date of injury. This guide covers the 2005 Permanent Disability Rating Schedule (PDRS) and the statutes around it. It is general information, not legal advice.

Which rules apply

The date of injury decides the formula.

The 2005 PDRS was adopted effective January 1, 2005 under 8 CCR 9805, and the DWC publishes it as a PDF. Older injuries can rate under an earlier schedule, so confirm the date of injury before you rely on any rating.

How a rating string is built

Every rating follows the same order:

1. Impairment number: the body part and method, from the PDRS.
2. Whole person impairment (WPI): from the evaluator, using the AMA Guides, Fifth Edition.
3. Adjustment for earning capacity: the FEC factor for pre-2013 injuries, which runs from 1.1 to 1.4, or a flat 1.4 for 2013-and-later injuries.
4. Occupational group and variant: the worker's occupation at the time of injury moves the rating up or down for that body part.
5. Age adjustment: the worker's age at the date of injury.

The DWC's own FAQ shows a 2013-or-later example: 15.03.01.00 - 8 - [1.4]11 - 340G - 13 - 15 PD. That reads as impairment number 15.03.01.00, 8% WPI, 11 after the 1.4 adjustment, occupational group 340 with variant G giving 13, and 15% after age.

Combining impairments

When there is more than one impairment, ratings are combined, not added. The PDRS uses the formula a + b(1 - a): combine the two largest first and round at each step. The DWC's FAQ says to use the Combined Values Chart in the PDRS, not the chart in the AMA Guides.

For injuries on or after January 1, 2013, Labor Code 4660.1 also bars increases for sleep dysfunction, sexual dysfunction or a psychiatric disorder arising from a compensable physical injury, though treatment is still provided. The psychiatric exception covers a victim of a violent act and a catastrophic injury, such as loss of a limb, paralysis, a severe burn or a severe head injury.

Apportionment

Apportionment often moves a case more than the WPI does.

• Labor Code 4663 bases apportionment on causation. The evaluator must give an approximate percentage of the PD caused by the industrial injury and by other factors, before or after it. A report without that is incomplete on apportionment.
• Labor Code 4664 limits the employer's liability to the percentage directly caused by the industrial injury. A prior PD award is conclusively presumed to still exist, and ratings to one region of the body can't exceed 100% over a lifetime, except in cases under Labor Code 4662.

Read every apportionment opinion for its reasoning: how the evaluator got from the history to the percentage. An unexplained number is worth a deposition or supplemental report.

The strict rating isn't always the end of it. The DWC's rating FAQ notes that, under the Guzman appellate decision, the PDRS is prima facie evidence and can be rebutted, and the Disability Evaluation Unit will issue both a standard rating and an Almaraz/Guzman rating where one applies.

What PD pays

For injuries from 2005 through 2012, Labor Code 4658(d) can raise or lower PD payments by 15% depending on whether the employer offers regular, modified or alternative work within 60 days of permanent and stationary status, for employers with 50 or more employees.

Getting a rating from the DEU

The DWC's Disability Evaluation Unit (DEU) rates reports using the PDRS (8 CCR 10150). Summary ratings under 8 CCR 10160 are for unrepresented employees. Consultative ratings under 8 CCR 10166 can be requested on AME, QME or treating reports in represented cases, and aren't admissible in judicial proceedings. Many applicant firms rate reports themselves first and request a consultative rating when the parties disagree.

Checklist for every final report:

• Date of injury and which formula applies.
• WPI for each body part, with the AMA Guides table cited.
• Occupation at the time of injury and the group number you'd use.
• Age at the date of injury.
• Apportionment percentages and the evaluator's reasoning.
• Add-ons the report claims, checked against Labor Code 4660.1 for 2013-and-later injuries.
• Whether an Almaraz/Guzman rebuttal is argued, and on what basis.
• PD advances paid so far, against the rating.

Where ratings get disputed

Most rating disputes come down to a few questions, and knowing them helps when you read a defense rating:

• The impairment method. Evaluators can rate the same body part different ways under the AMA Guides. A different method can change the WPI more than any later step.
• The occupational group. The worker's actual duties at the time of injury decide the group. A job title alone can put the worker in the wrong group and move the rating.
• Combining. Whether impairments are combined or added, and in what order, changes the result. The PDRS chart controls.
• Apportionment. Whether the evaluator explained how and why, and whether a prior award really covered the same region.
• Rebuttal. Whether the standard rating fairly reflects the worker's impairment, or an Almaraz/Guzman analysis applies.
• Date-of-injury rules. Whether the 1.4 multiplier, the 2005-2012 return-to-work adjustment or the add-on limits in Labor Code 4660.1 apply at all.

Keep each side's rating string in the file. When the numbers differ, the strings show exactly which step is in dispute.

How a firm can track this

Ratings feed settlement value, and settlement value feeds case decisions, so keep the evaluator's numbers, the rating string and the PD paid on the case. Our QME and AME guide covers getting the report in the first place.

PlaintiffStack doesn't calculate PD ratings. Firms rate with the PDRS, rating software or the DEU. On workers' comp cases, the Benefits page can show PD advances next to TD, and the med-legal page keeps each evaluator's report and the deadlines around it.