Guides / 38 CFR Part 4

38 CFR Part 4 Study Guide for the Claims Agent Exam: the Rating Schedule, Combined Ratings, and TDIU

If Part 3 is the rulebook for whether a veteran gets service connection, Part 4 is the price list: the Schedule for Rating Disabilities. It assigns every service-connected condition a percentage, and it supplies the math VA uses to combine those percentages. The accreditation exam does not ask you to recite hundreds of diagnostic codes from memory. It tests whether you understand the framework: how ratings are assigned, how they combine, what pyramiding is, and when a veteran who is not 100 percent schedular can still be paid at the 100 percent rate.

What Part 4 is and how it is organized

Part 4 contains the schedules VA uses to evaluate service-connected disabilities. Each condition is matched to a diagnostic code, an arbitrary number that points to a set of rating criteria, and the criteria produce a percentage in 10-point steps from 0 to 100. The percentages reflect the average impairment in earning capacity that the condition causes in civilian occupations, not the veteran's actual lost wages. That distinction matters: ratings measure average functional loss, and the exam will test whether you know the difference.

The part opens with general rating principles, then walks through the body systems in clusters. The musculoskeletal system runs from 4.40 through 4.73, with the big diagnostic schedule at 4.71a. Then come the eye (4.75 through 4.84a), hearing and other sense organs (4.85 through 4.87a), the respiratory system (4.96 and 4.97), the cardiovascular system (4.100 through 4.104), the digestive system (4.110 through 4.114), the genitourinary system (4.115a and 4.115b), gynecological and endocrine conditions (4.116a through 4.119), neurological conditions (4.120 through 4.124a), and mental disorders (4.125 through 4.130). Dental, oral, and skin conditions round out the schedule. For exam purposes, you need to know that the clusters exist and roughly what each covers, not the code for every condition.

The evaluation framework: 4.1 through 4.10

The first ten sections are the highest-yield study material in Part 4, because they state principles the exam loves to test:

• 4.1, essentials of evaluative rating. Ratings are based on the effect of the disability on the veteran's ordinary activity, including employment. The full history matters, not just the current snapshot.
• 4.2, interpretation of examination reports. Examiners' reports must be read as a whole. A single stray sentence does not control the rating.
• 4.3, resolution of reasonable doubt. When the evidence is in approximate balance, the doubt is resolved in the veteran's favor. This is the rating-schedule expression of the benefit-of-the-doubt rule the exam also tests under 38 U.S.C. 5107(b).
• 4.6, evaluation of evidence. Every element of the rating must be considered, and the rating must account for the whole record.
• 4.7, higher of two evaluations. Where the evidence supports two ratings under the same diagnostic code, the higher one is assigned.
• 4.10, functional impairment. The rating must reflect functional loss, what the veteran can actually do, not just the diagnosis name.

These six sections are short, and they show up on the exam as principle questions. Read the actual text of each one on eCFR. They take ten minutes and they pay off for years.

Combined ratings: the math of 4.25

Disability percentages are not added. They are combined under the table in 38 CFR 4.25, and the logic is the whole-person theory. A veteran starts at 100 percent efficiency. The most severe disability takes its percentage of the whole person, and each subsequent disability takes its percentage of what remains.

Work the classic example from the regulation itself. A 60 percent disability leaves the veteran 40 percent efficient. A further 30 percent disability does not take 30 percent of the original 100, it takes 30 percent of the remaining 40 percent efficiency, which is 12 percent. That leaves 28 percent efficiency, so the veteran is 72 percent disabled. Ratings are combined in order of severity, highest first, and the conversion to the nearest number divisible by 10 happens only once, at the end. Values ending in 5 round upward. So 72 percent becomes a final 70 percent rating.

Try a three-rating example. Ratings of 50, 30, and 10 percent. Start at 100 percent efficiency. The 50 takes half, leaving 50. The 30 takes 30 percent of 50, which is 15, leaving 35. The 10 takes 10 percent of 35, which is 3.5, leaving 31.5. The combined disability is 68.5 percent, which rounds to 70 percent. Simple addition would have said 90 percent. VA math says 70. That gap is why veterans hire representatives who can read decision letters, and it is why the exam tests this math.

The bilateral factor: 4.26

When partial disability results from disease or injury of both arms, both legs, or paired skeletal muscles, 4.26 adds a bilateral factor. The procedure: combine the ratings of the disabilities affecting the paired extremities in the usual way, then add 10 percent of that combined value (do not combine it), and only then proceed with combining the remaining ratings or converting to the final degree of disability.

Example. A veteran has 20 percent for the right knee and 20 percent for the left knee, plus 30 percent for PTSD. First combine the knees: 20 and 20 combine to 36 percent. The bilateral factor adds 10 percent of 36, which is 3.6, giving 39.6 percent for the bilateral pair. Treat that 39.6 as one rating and combine with the 30 percent PTSD rating: 30 percent of the remaining 60.4 percent efficiency is 18.12, so the combined value is 57.72 percent, which rounds to 60 percent. Without the bilateral factor, the math would come out lower.

Two conditions on the bilateral factor that the exam tests. First, it applies only when there is a compensable (nonzero) rating on each side. Two zero-percent ratings do not earn a bilateral factor. Second, the factor is added, not combined. If an answer choice combines the 10 percent like another disability, it is wrong.

Total ratings and TDIU: 4.15 and 4.16

A total schedular rating under 4.15 reflects impairment severe enough that the average person could not follow a substantially gainful occupation. But many veterans who cannot work do not reach 100 percent by schedular math. That is where 4.16 comes in: total disability ratings for compensation based on individual unemployability, universally called TDIU.

The schedular gateway for TDIU has two doors. If there is only one service-connected disability, it must be rated at 60 percent or more. If there are two or more disabilities, at least one must be rated at 40 percent or more and the combined rating must be 70 percent or more. Disabilities arising from a common etiology or a single accident can be counted as one disability for this purpose. Meeting the percentages does not automatically grant TDIU; the veteran must show the service-connected disabilities actually prevent substantially gainful employment. And 4.16(b) preserves an extraschedular path: cases that do not meet the percentage gates can be referred for special consideration.

Section 4.17 covers the parallel concept for pension: total disability ratings for pension based on unemployability. Keep the two straight. Compensation unemployability is 4.16, pension unemployability is 4.17.

Zero percent and temporary ratings: 4.28 through 4.31

Not every service-connected condition earns money today, and the exam tests the vocabulary:

• 4.28, prestabilization ratings. Ratings assigned from the date of discharge before the condition has stabilized.
• 4.29, ratings for disabilities requiring hospital treatment or observation. Temporary total ratings during qualifying hospitalization.
• 4.30, convalescent ratings. Temporary total ratings during convalescence after surgery or treatment.
• 4.31, zero percent evaluations. Where the schedule does not provide a zero percent evaluation for a diagnostic code, a zero percent rating is assigned when the requirements for a compensable evaluation are not met. A zero percent rating still means service connection is established, which matters for future increases and for secondary claims.

How to study Part 4 without drowning in it

The number one mistake candidates make with Part 4 is trying to memorize diagnostic codes. The exam cannot fairly test hundreds of codes, and it does not try. What it tests is the framework around the codes. Spend your time in this order:

• Read 4.1 through 4.10 in full. Short sections, high exam yield, and they read like the exam questions themselves.
• Master 4.14, 4.15, 4.16, 4.25, 4.26, and 4.31. Pyramiding, total ratings, TDIU gates, combined ratings math, the bilateral factor, and zero percent evaluations. These six sections are the core of every Part 4 question.
• Learn the body-system clusters. Know which range covers musculoskeletal, mental disorders, neurological, and the rest, so a question that names a diagnostic code range does not scare you.
• Drill the math. Run the calculator above with random rating sets until the whole-person logic is reflexive. The exam's combined-ratings questions are free points once the method is automatic.
• Connect Part 4 to Part 3. Service connection (Part 3) decides whether a condition is compensable; the rating schedule (Part 4) decides how much. Protected ratings live in Part 3 (3.344 stabilization, 3.951 and 3.952 long-held ratings), and questions love to cross the boundary.

Part 4 rewards the candidate who thinks like a rater: read the evidence as a whole, resolve doubt for the veteran, rate each distinct function once, and do the math in the right order. Learn that posture and the section numbers follow naturally.

Sources

• 38 CFR Part 4, Schedule for Rating Disabilities. Full text: eCFR Part 4.
• 38 CFR 4.25, Combined ratings table. Full text: eCFR 4.25.
• VA.gov: About VA disability ratings, VA's plain-language overview of how ratings and combined ratings work.

This page is for general information only, not legal advice. It is an independent study resource, not affiliated with or endorsed by the U.S. Department of Veterans Affairs.