What Is MMA / MMI in California Workers' Compensation?

What does whole person impairment mean?

Whole person impairment is a score from 0 to 100. It shows how much your injury limits your whole body, not just one part.

The number is not a guess. Your doctor follows a thick medical book. It is called the AMA Guides to the Evaluation of Permanent Impairment.

First your doctor waits until you are as healed as you will get. This stage has a name. It is called permanent and stationary, or P and S. Some doctors say you have reached maximum medical improvement.

At that point the doctor writes a final report. The report gives your whole person impairment, often shortened to WPI. A bad back might rate 8 percent. The loss of a hand rates far more.

Whole person impairment is not the percent of your body that is gone. It measures lost function. Your doctor checks your range of motion, your strength, and any nerve damage. Two bad backs can rate very differently.

You may also hear the term AMA Guides Fifth Edition. That is the exact version California uses. Older or newer editions do not apply here. A rating built on the wrong edition can be challenged.

Do not let anyone rush this step. If you settle before you are healed, you may lose money you cannot get back.

How is my impairment rating built, step by step?

Your doctor finds a raw impairment number. The state then adjusts it for your job and age. That gives your final disability rating.

The rating is built in clear steps. Each step can change the number. Here is the order it follows.

1. Your doctor finds your whole person impairment from the AMA Guides.
2. That number is adjusted for how hard your job is on your body.
3. The number is then adjusted for your age.
4. This math is set by Labor Code 4660.1, and it can move your rating up or down.
5. The final rating sets your weeks of pay under Labor Code 4658.

Why adjust for your job? A roofer who hurts a knee suffers more than an office clerk. So the same injury can rate higher for hard physical work.

Age matters too. The law assumes an older body heals more slowly. Both shifts are built into the rating. This is why two people with the same injury can get very different ratings.

The doctor's raw number is only the start. A trained rater turns it into the official rating. They use a state schedule to do the math. You have the right to see how they got there.

The result is written as a rating string. It might look like a code full of numbers and letters. Do not let that scare you. Your lawyer can read it and explain each part in plain words.

What is my impairment rating worth in dollars?

Your rating sets a number of weeks. Each week pays about two-thirds of your wage. A higher rating means more weeks and more money.

Permanent disability pay runs from $160 to $290 a week in 2026. Your rating sets how many weeks you collect. The table below shows what each rating is worth.

So a 30 percent rating equals 130 weeks of checks. A 60 percent rating equals 350 weeks. The jump in value is large, so every point counts.

A rating of 70 percent or more adds a life pension. That is a small check that lasts the rest of your life.

This money is yours to keep. It does not have to be paid back. You can use it for rent, bills, or anything you need.

What if you have more than one hurt body part? The doctor rates each part on its own. Then a formula blends them into a single rating. Adding every injury can raise your total, so none should be left out.

One more rule can shift your pay. If your boss offers you steady work, your rating can drop 15 percent. If there is no offer, it can rise 15 percent. This bump comes from Labor Code 4658(d).

How do I challenge a low impairment rating?

A low rating is not final. You can get a second opinion from a state doctor. You can also fight unfair blame for old injuries.

If you disagree with the rating, you can object. The state then sends a list of three doctor names. Each side strikes one name. The doctor left over becomes your QME. This panel process comes from Labor Code 4062.2.

If you have a lawyer, both sides can instead agree on one doctor. That shared expert is called an AME. A strong report from this doctor can lift your rating a lot.

Watch for one common move by the insurer. They may blame your pain on aging or an old injury. This is called apportionment, set by Labor Code 4663. It can cut your rating and shrink your check.

A good lawyer reviews the report line by line. Many ratings use the wrong job group or miss a hurt body part. Fixing those errors can be worth thousands of dollars.

You do not have to figure this out alone. Bring the report to a lawyer who knows ratings. A quick review can show if your number is fair.

There are deadlines to object, so do not wait. If you sit on a low rating, you can lose the right to fight it. The moment a report lands, have someone review it fast.

One last warning. Do not sign a settlement before you understand the rating. Once you sign, that low number can be locked in. Talk to a lawyer first, while you still have options.