Veterans Benefits: Service Connection, Ratings, and the Appeals Process

Summary. This article explains the three elements of service connection and the routes to establishing them, presumptive and secondary connection, how the rating schedule and combined ratings table work, what TDIU provides, how effective dates determine back pay, and the three decision review lanes and how to choose among them.

The VA benefits system is unlike almost every other adjudicative system an American will encounter, and the differences run in the claimant's favor.

It is non-adversarial by statute. There is no opposing party. The agency has an affirmative duty to assist in obtaining evidence, including ordering medical examinations at government expense. And when the evidence for and against a claim is in approximate balance, the statute directs that the benefit of the doubt goes to the claimant — a standard materially more generous than the preponderance rule that governs civil litigation.

It is also, notoriously, slow, procedurally intricate, and capable of denying claims that should plainly be granted. Both things are true, and the reconciliation is that the system's generosity is largely procedural: it rewards claimants who understand the sequence and the evidence, and it does not rescue those who do not.

This article explains the sequence.

Part I: The three elements

38 U.S.C. § 1110 provides the basic entitlement: compensation for disability resulting from personal injury or disease incurred in or aggravated by active military, naval, air, or space service, where the disability was not the result of the veteran's own willful misconduct or abuse of alcohol or drugs.

That produces three elements, and nearly every denial turns on the third:

A current disability. A diagnosed condition, present now. A condition that resolved before the claim generally supports nothing.
An in-service event, injury, or disease. Documented in service records where possible, and provable by lay evidence where not.
A nexus — a medical link between the two.

The nexus is where claims are won and lost. It is a medical opinion, and the language matters: an examiner who says a condition is "at least as likely as not" related to service has satisfied the standard, while one who says it "could be" or "may be" related has generally not. "At least as likely as not" — meaning a probability of 50% or greater — is the phrase to look for and to ask for.

The duty to assist. 38 U.S.C. § 5103A requires VA to make reasonable efforts to obtain relevant records — service records, VA and private treatment records, Social Security records — and to provide a medical examination or obtain an opinion when necessary to decide the claim. A failure to obtain identified records, or to provide an adequate examination, is itself a ground for appeal, and it is one of the most common.

The benefit of the doubt. 38 U.S.C. § 5107(b) provides that when there is an approximate balance of positive and negative evidence, the Secretary shall give the benefit of the doubt to the claimant. This is not a formality: a decision that weighs conflicting medical opinions and finds them in equipoise must resolve in the veteran's favor, and a decision that does not say why one opinion outweighed another is appealable on that basis.

Part II: Routes to service connection

Direct. The three elements, established by evidence.

Presumptive. For certain conditions and certain service, the law presumes the nexus, eliminating the hardest element. The major categories:

Chronic diseases manifesting to a compensable degree within one year of separation (arthritis, hypertension, diabetes, psychoses, and others).
Prisoners of war, with specific conditions.
Agent Orange / herbicide exposure, for veterans who served in specified locations, covering a list of conditions including several cancers, ischemic heart disease, Parkinson's disease, and type 2 diabetes.
Gulf War undiagnosed illnesses and medically unexplained chronic multisymptom illnesses, which is unusual in permitting service connection without a diagnosis.
Burn pit and airborne hazard exposures under the PACT Act, which created a large set of presumptive conditions and expanded the covered locations and periods — the most significant expansion of eligibility in decades, and the reason many previously denied claims should be refiled.
Radiation exposure, camp Lejeune contaminated water, and several others.

Secondary. A condition caused or aggravated by an already service-connected condition. This is the most underused route in the entire system. Examples that are routinely granted and routinely never claimed: depression secondary to chronic pain; sleep apnea aggravated by service-connected PTSD or by weight gain from a service-connected condition; hypertension secondary to diabetes; a knee condition secondary to an altered gait from a service-connected ankle; erectile dysfunction and gastrointestinal conditions secondary to psychiatric medication.

Aggravation. A pre-existing condition made worse by service. The presumption of soundness applies: a veteran is presumed sound at entry except for defects noted at examination, and the presumption is rebutted only by clear and unmistakable evidence both that the condition pre-existed and that it was not aggravated.

§ 1151. Disability caused by VA medical care or vocational rehabilitation, compensated as if service-connected.

Part III: How ratings work

38 U.S.C. § 1155 directs the Secretary to adopt a schedule for rating disabilities based, as far as practicable, on the average impairment of earning capacity resulting from each injury in civil occupations. The schedule assigns diagnostic codes and criteria; each condition is rated from 0% to 100% in increments.

A 0% rating matters. It establishes service connection, which means later worsening can be rated higher, secondary conditions can be claimed, and treatment priority improves. Never treat a 0% grant as a denial.

Combined ratings are not additive, and this surprises nearly everyone. The combined ratings table works on remaining efficiency: a 50% disability leaves 50% efficiency; adding a 30% disability takes 30% of the remaining 50%, which is 15 — producing 65%, rounded to the nearest 10, for a combined 70%.

A worked example. Ratings of 50%, 30%, and 20%. Start at 100% efficiency. The 50% leaves 50% efficient → 50% combined. The 30% takes 30% of the remaining 50 = 15 → 65% combined, 35% efficient. The 20% takes 20% of the remaining 35 = 7 → 72% combined. Rounded to the nearest 10: 70%.

Three ratings totaling 100 on paper produce 70 in fact. This is why "I'm at 100% because I have five 20s" is wrong, and why the marginal value of an additional low rating declines sharply as the combined figure rises.

The bilateral factor adds an additional percentage where there are compensable disabilities of both arms, both legs, or paired skeletal muscles.

Special monthly compensation is available above the schedular ratings for specified losses — loss of use of a limb, blindness, deafness, aid and attendance, housebound status — and it is frequently unclaimed.

Effective dates determine back pay, and they are worth more than most claimants realize. The general rule is the date of receipt of the claim, or the date entitlement arose, whichever is later. Two exceptions matter enormously: an intent to file submission preserves the effective date for up to a year while evidence is gathered; and a claim filed within one year of separation takes an effective date of the day after separation.

Part IV: Total disability based on individual unemployability

TDIU pays at the 100% rate without a 100% schedular rating, where the veteran is unable to secure or follow a substantially gainful occupation because of service-connected disabilities.

Schedular TDIU requires one disability rated 60% or more, or a combined rating of 70% or more with at least one disability at 40% or more. Extraschedular TDIU is available below those thresholds on referral, where the case presents an exceptional picture.

Two points that decide TDIU claims. First, "substantially gainful" is not the same as "any work." Marginal employment — earnings below the poverty threshold, or work in a protected environment such as a family business or a sheltered position with substantial accommodation — does not defeat the claim. Second, the question is occupational impairment, not medical severity: what wins these claims is evidence about work — an employment history showing declining hours and lost jobs, a former employer's statement about accommodations provided and absences tolerated, and a vocational expert's opinion tying the service-connected limitations to an inability to sustain employment.

Part V: The three decision review lanes

The Appeals Modernization Act replaced a single, notoriously slow appeal path with three lanes. Each has a one-year deadline from the decision, and choosing correctly is the most consequential decision in a VA appeal.

1. Supplemental claim. File when you have new and relevant evidence. The standard is lower than the old "new and material" test — evidence need only tend to prove or disprove a matter at issue. VA's duty to assist reattaches. This is the right lane when the denial was for lack of evidence, particularly a missing nexus opinion, and it is the only lane that permits new evidence.

2. Higher-level review. A more senior adjudicator reviews the same record de novo. No new evidence may be submitted. An informal conference with the reviewer may be requested, and this lane exists for clear errors in applying the law or the rating criteria to the evidence already there. Use it when the record supports the grant and the decision got it wrong.

3. Notice of disagreement to the Board of Veterans' Appeals, under 38 U.S.C. § 7104, with three sub-options: direct review (no new evidence, no hearing — fastest); evidence submission (90 days to submit additional evidence, no hearing); or hearing (before a Veterans Law Judge, with a 90-day post-hearing evidence window — slowest by a wide margin).

How to choose. Missing evidence, especially a nexus opinion → supplemental claim. The evidence is there and the decision misapplied the criteria → higher-level review. A complex legal question, or the RO has denied repeatedly → the Board. And note that lanes may be used sequentially: a Board denial may be followed by a supplemental claim with new evidence, and the effective date is preserved so long as each step is taken within one year.

Part VI: Above the Board

The Court of Appeals for Veterans Claims, under 38 U.S.C. § 7252, has exclusive jurisdiction to review Board decisions. Appeal must be filed within 120 days of the Board's decision. The Court reviews findings of fact for clear error and questions of law de novo, and it frequently remands for inadequate reasons and bases — a Board decision that does not explain why it credited one medical opinion over another is vulnerable.

The Federal Circuit reviews the Veterans Court on questions of law and statutory interpretation, and the Supreme Court above that.

The Equal Access to Justice Act provides attorney's fees against the government where the government's position was not substantially justified, which is what makes representation at the Court economically available.

Clear and unmistakable error is a separate collateral route: a final decision may be revised at any time where the error is undebatable and would have manifestly changed the outcome. The standard is very high — a mere disagreement with how evidence was weighed does not qualify — but a successful CUE motion revises the effective date, which can produce decades of retroactive benefits.

Part VII: The other programs

Pension is a needs-based benefit for wartime veterans who are permanently and totally disabled or 65 or older, with income and net worth limits and a three-year lookback on asset transfers. Aid and Attendance and Housebound are increased pension rates for those needing help with daily activities.

Dependency and Indemnity Compensation (DIC) is paid to a surviving spouse, child, or parent where the veteran died from a service-connected condition, or was continuously rated totally disabled for a specified period before death. It is substantial, and it is routinely unclaimed by surviving spouses who do not know it exists.

Health care eligibility is organized by priority group, and the PACT Act substantially expanded it.

Education — the Post-9/11 GI Bill, Montgomery GI Bill, Dependents' Educational Assistance, and Veteran Readiness and Employment (formerly vocational rehabilitation), which pays for training and supports and is underused.

Home loan guaranty, with a funding fee waived for veterans with a service-connected disability rating.

Burial benefits, plot allowance, headstone or marker, and burial in a national cemetery.

Character of discharge governs access to nearly all of it. A dishonorable discharge generally bars benefits; other-than-honorable discharges require a character of discharge determination, and several categories — including discharges attributable to conditions now understood as PTSD, traumatic brain injury, or military sexual trauma — have been the subject of policy changes and successful discharge upgrade applications through the service branch review boards. A veteran with an other-than-honorable discharge should not assume ineligibility; the upgrade route exists and it works.

Part VIII-A: The C&P examination

The compensation and pension examination is where most claims are actually decided, and most veterans walk into one without understanding what it is.

What it is not. It is not treatment, and the examiner is not your doctor. The examination exists to produce a written opinion on two questions: is the claimed condition related to service, and how severe is it measured against the rating criteria. The examiner may be a VA clinician or a contractor, may have twenty minutes, and will complete a Disability Benefits Questionnaire — a structured form keyed to the rating schedule.

What to do before. Read the rating criteria for your condition so you know what the examiner is measuring. Bring a written summary: your diagnoses, your treating providers, your medications, and a short symptom log. Bring copies of private records the examiner may not have.

What to say. Describe your worst days and your average days, not your best. This is the single most common and most costly mistake: veterans, trained not to complain, minimize. If you can walk a mile on a good day but cannot get out of bed twice a week, both facts belong in the record — and the second one is the one that rates.

Be specific and functional. Not "my back hurts" but "I can stand for about ten minutes before I have to sit; I stopped mowing the lawn in 2022; I miss two or three days of work a month; I sleep four hours because of the pain." Frequency, duration, and what you have stopped doing.

Do not exaggerate either. Examiners assess consistency, and a report that is contradicted by treatment records or by observed behavior damages everything else in the file.

Afterward, get the examination report. Request it, read it, and check three things: did the examiner review the claims file (the report says); did the examiner address all the claimed conditions and all the theories, including secondary and aggravation; and does the opinion use the correct standard — "at least as likely as not" — with a stated rationale.

If the examination was inadequate, say so in writing. An examination that omitted a condition, was conducted without the records, rests on an incorrect factual premise, or gives a conclusion without reasoning is not adequate, and VA's duty to assist requires an adequate examination. Requesting a new one, with the specific defect identified, is a routine and frequently successful step — and the inadequacy is itself a ground for appeal.

Part IX: Evidence that wins

Three categories of evidence do most of the work, and two of them cost nothing.

The nexus opinion. The single most valuable document in a claim. What makes one persuasive:

The provider states they reviewed the service treatment records and the claims file, and identifies what they reviewed.
The opinion uses the phrase "at least as likely as not" (50% probability or greater).
It gives a rationale — the mechanism, the medical literature, the chronology — rather than a conclusion.
It addresses and rejects the alternative explanations the VA examiner relied on.
It comes from a provider with relevant expertise who has actually treated or examined the veteran.

A one-line letter saying "his knee is probably from the Army" is worth very little. A two-page opinion explaining why the documented 2004 injury, the continuity of complaints, and the degenerative pattern support a service relationship is worth a great deal.

Lay statements. Free, competent evidence, and radically underused. A veteran is competent to describe what they experienced and observed — pain, symptoms, what happened during an incident — and so are the people around them. Get statements from:

A spouse or partner describing the change after service: sleep, temper, avoidance, physical limitation.
Someone who served with you, describing the event or the symptoms at the time — critical where records are missing.
An employer or coworker describing accommodations, absences, and declining performance.
The veteran's own statement, describing continuity of symptoms from service to now.

Each should be specific, dated, signed, and written in the person's own words. Buddy statements are frequently the only evidence of an unreported in-service event, and the Board can and does grant on them.

Records the veteran must chase. VA's duty to assist is real but not omniscient. Identify and provide: private treatment records; personnel records showing duty assignments, locations, and dates (which prove exposure for presumptive claims); unit records and after-action reports; Social Security disability records; and, for personal-assault or military sexual trauma claims, the markers that regulations expressly permit as alternative evidence — a request for transfer, a sudden change in performance, disciplinary or behavior changes, statements to a counselor, clergy, or family member, or an unexplained economic or social change.

Part X: Common denials, and what each one actually means

Decision letters are written in a formula. Reading it correctly tells you which lane to choose.

The letter says	What it means	The right response
"No evidence of a current disability"	No diagnosis in the record	Get diagnosed. Supplemental claim with the diagnosis
"No evidence of an in-service event"	The records do not show it	Buddy statements, personnel records, unit records, markers. Supplemental claim
"The evidence does not establish a link"	No nexus opinion — the most common denial	Obtain a nexus opinion in the right words. Supplemental claim
"The examiner opined it is less likely than not"	A negative VA opinion controls the file	A private opinion that addresses and rebuts the VA examiner's rationale. Supplemental claim
"Not shown to have been incurred in or aggravated by service"	Generic — read the evidence list to see what was missing	Depends; usually a nexus problem
"The condition is not compensable under the rating criteria"	Rated 0% or denied on severity	Higher-level review if the evidence meets the criteria; supplemental claim with new severity evidence
"You did not report for the examination"	A missed C&P	Explain in writing and request rescheduling immediately
Evidence list omits records you submitted	A duty to assist failure	Point to it specifically; this is a strong appeal ground
No explanation of why one opinion outweighed another	Inadequate reasons and bases	Higher-level review, or a Board appeal — this is what the Veterans Court remands for

Two things to do with every denial. Read the "Evidence" list and confirm everything you submitted appears in it. And read the "Reasons for Decision" to identify which of the three elements failed — because that determines whether you need new evidence (supplemental claim) or a better reading of the existing record (higher-level review).

Part XI: Where the money actually is

Several parts of the system are worth substantially more than the base rating, and are claimed far less often than they should be.

Dependents. A veteran rated 30% or higher receives additional compensation for a spouse, children, and dependent parents. It requires filing a dependency claim; it is not automatic, and it is retroactive only in limited circumstances. File it the day a rating reaches 30%.

TDIU, discussed above — the 100% rate without a 100% schedular rating.

Special monthly compensation, above the schedule, for loss of use, aid and attendance, housebound status, and specified combinations. SMC(k), SMC(s), and aid and attendance are the most commonly missed.

Effective dates. An intent to file preserves up to a year of back pay for the cost of a form. A claim filed within one year of separation reaches back to the day after separation. And a claim for increase can reach back one year before filing where the worsening is factually ascertainable from the records.

Automobile and adaptive equipment grants, specially adapted housing grants, clothing allowance for veterans whose prosthetics or medications damage clothing, and VA life insurance programs.

Concurrent receipt. Historically military retired pay was offset dollar-for-dollar by VA compensation. Concurrent Retirement and Disability Payments now permit retirees with 20 years of service and a rating of 50% or more to receive both, and Combat-Related Special Compensation provides a separate tax-free payment for combat-related disabilities. Retirees frequently do not know which they qualify for, and the two cannot be received simultaneously — an annual election applies, and the better choice depends on the numbers.

State benefits, which are entirely separate and vary enormously: property tax exemptions (in some states total, for veterans at 100%), tuition waivers for veterans and dependents, hunting and fishing licenses, park access, vehicle registration, and state veterans homes. A county or state veterans service officer knows these and the VA does not administer them.

And DIC for survivors, which is substantial, is paid where the veteran died of a service-connected condition or was rated totally disabled for a specified period before death — and which surviving spouses routinely never claim because nobody told them it existed.

Part XI-A: Claims that need special handling

Four categories follow different evidentiary rules, and treating them like ordinary claims is why they get denied.

Military sexual trauma and personal assault. These events are frequently unreported, so the service records contain nothing. VA regulations expressly permit alternative evidence — "markers": a request for transfer, a sudden decline in performance or attendance, disciplinary action or behavior changes, substance use beginning at that time, a pregnancy test or treatment for a sexually transmitted infection, statements to a counselor, chaplain, family member, or friend, or an unexplained economic or social change. A behavioral change documented in the personnel file, with a lay statement explaining it, can establish the stressor. Do not conclude a claim is impossible because nothing was reported.

PTSD stressors. For a combat veteran, or for a veteran whose stressor relates to fear of hostile military or terrorist activity, the stressor may be established by the veteran's own testimony alone if consistent with the circumstances of service and confirmed by a VA psychiatrist or psychologist. Otherwise corroboration is required, and the productive sources are unit records, after-action reports, morning reports, and buddy statements.

Gulf War illness. Uniquely, service connection is available for undiagnosed illnesses and medically unexplained chronic multisymptom illnesses — chronic fatigue, fibromyalgia, functional gastrointestinal disorders — without a diagnosis at all. Claims are frequently denied because an examiner attributes symptoms to a diagnosed condition instead; the answer is an opinion addressing the regulation's actual framework.

Presumptive claims after the PACT Act. The Act added a large set of presumptive conditions and expanded the covered locations and periods for burn pit and toxic exposure. Two consequences: previously denied claims should be refiled where the condition is now presumptive, and the effective date rules for these claims are specific and worth checking, because in some circumstances they reach back further than the general rule.

And one more that is not a category but a habit: claim the secondary conditions at the same time as the primary. Depression secondary to chronic pain, sleep apnea aggravated by PTSD, hypertension secondary to diabetes, a contralateral joint from an altered gait, and gastrointestinal or sexual dysfunction from psychiatric medication are granted routinely and claimed rarely. The nexus is easier — it links two medical conditions rather than a condition and a decades-old event — and each one raises the combined rating.

Part XI-B: Three claims, worked through

The knee that was denied for want of a nexus. A veteran injured his knee on a training exercise in 2004, was treated at sick call twice, and separated in 2006. He filed in 2023 with an X-ray showing degenerative changes. Denied: "the evidence does not establish a link between your current condition and service."

What was missing was one document. He obtains an opinion from his orthopedist who reviews the service treatment records and writes that the 2004 injury, the documented complaints, the absence of intervening trauma, and the unilateral degenerative pattern make it "at least as likely as not" that the current condition is related to service — with a stated rationale. He files a supplemental claim (the only lane that accepts new evidence). Granted at 10%, with an effective date reaching back to the original 2023 claim, because the supplemental claim was filed within a year.

The rating that was correct and the decision that was wrong. A veteran rated 30% for PTSD documents, in her treatment records, panic attacks more than once a week, impaired judgment, and difficulty adapting to stressful circumstances — criteria that appear in the 70% level of the rating schedule. The decision recites the records and assigns 30% without explaining why.

This is a higher-level review case, not a supplemental claim. The evidence is already in the file; the error is in applying the criteria to it. She requests an informal conference and identifies, by page, the record entries matching each 70% criterion. The senior reviewer increases the rating, effective the date of the original claim.

The veteran who was working, but not really. A veteran rated 70% combined works twelve hours a week at his brother-in-law's shop, earning under the poverty threshold, in a job created for him where he can leave when symptoms flare.

He assumes he cannot claim TDIU because he is employed. He can. Marginal employment — earnings below the poverty threshold, or work in a protected environment — does not defeat the claim. What wins it is evidence about work: an employment history showing declining hours and lost jobs, a statement from the brother-in-law describing the accommodations and the absences tolerated, and a vocational expert's opinion tying the service-connected limitations to an inability to sustain substantially gainful employment. Granted at the 100% rate.

What all three have in common. None turned on a new medical fact. Each turned on producing the right document, in the right words, in the right lane.

Part XI-C: Who may represent you, and what it costs

Representation in VA claims is regulated, and the economics are unusual enough to be worth stating plainly.

Accredited Veterans Service Organization representatives. Free, permanently. VSOs — the major national organizations and their state and county affiliates — accredit representatives who prepare and file claims, gather evidence, and represent at the Board. For an initial claim they are frequently as effective as anyone, and they cost nothing. This should be the first call.

State and county veterans service officers. Also free, and they know the state benefits — property tax exemptions, tuition waivers, state veterans homes — that the VA does not administer and does not tell you about.

Accredited attorneys and agents. By statute, they may not charge a fee for an initial claim. A fee may be charged only after VA issues an initial decision and the claimant files for review — typically 20% of retroactive benefits, paid directly by VA out of past-due amounts, and the agreement must be filed with VA. This is why representation costs nothing out of pocket and why attorneys concentrate at the appellate stages, where the retroactive amounts are large.

At the Court of Appeals for Veterans Claims, the Equal Access to Justice Act provides fees against the government where its position was not substantially justified — which is what makes appellate representation economically available at all.

Two warnings. First, only accredited representatives may assist for a fee, and unaccredited "claim sharks" charging a percentage of monthly benefits or a flat fee to file an initial claim are operating outside the accreditation system; several states have moved against them. Second, be skeptical of anyone who guarantees a rating, charges upfront for an initial claim, or asks for a share of your monthly benefit rather than past-due amounts.

How to choose. For a first claim, or a straightforward increase: a VSO. For a denial where the evidence is missing: a VSO or an accredited agent, and get the nexus opinion. For a complex legal question, repeated denials, TDIU, CUE, or an appeal to the Board or the Court: an accredited attorney. And verify accreditation — VA maintains a searchable list, and checking takes a minute.

Part XII: Frequently asked questions

How long does a claim take? Initial claims commonly run several months to over a year. Higher-level review is faster; a Board hearing is the slowest option by a wide margin.

Do I need a lawyer? Not to file. Accredited Veterans Service Organization representatives assist for free and are excellent at initial claims. Attorneys may charge fees only after an initial decision, typically 20% of retroactive benefits, and are most valuable at the Board and the Court.

What is an intent to file? A submission that preserves your effective date for up to a year while you gather evidence. File one the moment you decide to claim anything.

My claim was denied. Is that final? No. You have one year to choose a review lane, and lanes may be used in sequence with the effective date preserved.

Can I work and still get benefits? Yes, at schedular ratings. TDIU requires inability to maintain substantially gainful employment, which is not the same as any work at all.

What if my condition gets worse? File a claim for increase. The effective date can reach back up to one year before the claim where the increase is factually ascertainable.

Does a discharge upgrade help? It can restore eligibility for nearly everything. Apply to the service branch's discharge review board or board for correction of military records.

Part XIII: For veterans and families — what to do

File an intent to file today if you are considering any claim. It costs nothing and it can be worth a year of back pay.
Get your complete file: service treatment records, personnel file, and — for an existing claim — the claims file (C-file), which is what an adjudicator actually reads.
Claim everything, including at 0%. Service connection at 0% is a foundation for later increases and secondary claims.
Think secondary. Depression from chronic pain, sleep apnea aggravated by PTSD, hypertension from diabetes, a knee from an altered gait. These are granted routinely and claimed rarely.
Get a nexus opinion in the right words. "At least as likely as not," with a rationale explaining why, from a provider who has reviewed the records.
Write lay statements, and get them from people who knew you before and after — a spouse, a squad member, an employer. Lay evidence is competent to establish observable symptoms and continuity.
Attend every examination, and describe your worst days, not your best. Examiners record what you say.
Read the decision letter carefully. It states the evidence considered and the reason for denial, and it tells you which lane to choose.
Never miss the one-year deadline for a review lane, or the 120-day deadline to appeal a Board decision.
Use a free accredited representative. A VSO, a state or county veterans service officer, or an accredited agent — all free, all experienced, and none of them will charge you for the initial claim.

Primary authority

38 U.S.C. § 1110 — basic entitlement to wartime disability compensation.
38 U.S.C. § 1155 — the schedule for rating disabilities, based on average impairment of earning capacity.
38 U.S.C. § 5103 — notice to claimants and the duty to assist.
38 U.S.C. § 5107 — claimant responsibility and the benefit of the doubt.
38 U.S.C. § 7104 — jurisdiction of the Board of Veterans' Appeals.
38 U.S.C. § 7252 — jurisdiction of the Court of Appeals for Veterans Claims.
38 C.F.R. Part 3 (adjudication) and Part 4 (the rating schedule, including the combined ratings table at § 4.25 and TDIU at § 4.16); the Veterans Appeals Improvement and Modernization Act; the PACT Act.