A plain-English VA disability evidence guide

What is VA trying to decide?

For a direct service-connection claim, the evidence usually has to answer three different questions: What condition do you have now? What happened during service? What connects the two? A nexus letter belongs in that third box—but only when that is the box your claim still needs.

Choose your claim pathUse the worksheet
This is not an official VA scorecard. VA considers the whole record, and the proof changes with the type of claim. This guide translates VA’s published evidence requirements and current regulations into a working map you can use with an accredited representative or clinician.

Start with the right question

Choose the path that matches your claim.

A nexus letter can be central to one claim and unnecessary for another. Pick the path below to see what VA generally needs, what evidence may answer it, and whether a private medical opinion has a real job to do.

Direct service connection

You are saying that a current condition began in service or is otherwise connected to an event, injury, disease, or exposure during service.

What generally must be established

  • A current physical or mental disability
  • An event, injury, or disease during service
  • A link between the current condition and what happened in service

Evidence that may answer it

  • Current treatment records and testing
  • Service treatment or personnel records
  • Exposure or incident records
  • Lay or buddy statements about observable facts
  • A medical opinion explaining the connection
Where the nexus letter fits

It addresses the third element: the medical relationship between the present condition and the service evidence. It should explain why this veteran’s record supports the conclusion, not simply state that a connection exists.

Claim-path summaries are based on VA’s current Evidence Needed for Your Disability Claim guidance and 38 C.F.R. §§ 3.303 and 3.310.

Where the letter enters the record

A nexus letter is one part of an evidence chain.

The letter does not create the underlying facts. Its job is to answer a medical question using the facts and records that can be supported.

01

The condition

Medical records establish the diagnosis, symptoms, testing, and treatment history.

02

The service anchor

Records or competent statements establish the relevant event, injury, disease, exposure, or primary disability.

03

The medical question

The file is reduced to a precise question about direct causation, secondary causation, or aggravation.

04

The physician’s opinion

The clinician gives a conclusion and explains how the relevant facts and medical principles support it.

05

VA weighs the record

VA considers the opinion with the rest of the evidence and may still request a C&P examination or clarification.

Inside the clinical review

What the doctor is actually evaluating.

A responsible clinician is not looking for a phrase to paste into a letter. The physician is deciding whether the evidence can support a medical conclusion and whether that conclusion is inside the physician’s expertise.

Question 01

Is the current condition supported?

Does the file contain a diagnosis, testing, or clinical evidence adequate for the opinion being requested?

Question 02

What is the exact claim path?

Direct causation, secondary causation, and aggravation are separate medical questions with different evidence.

Question 03

Are the key facts established?

What can the clinician reliably say happened, and which records or competent statements support that history?

Question 04

Does the timeline make medical sense?

Onset, continuity, delayed diagnosis, treatment gaps, progression, and intervening events may all matter.

Question 05

What else could explain it?

A credible analysis considers contrary findings, alternative causes, risk factors, and the condition’s natural course.

Question 06

Does the literature fit this veteran?

Research can support the medical reasoning, but it has to be applied to the individual facts rather than cited in the abstract.

Question 07

Can the probability be stated?

The conclusion should answer the actual medical question without relying on speculation or disguising uncertainty.

Question 08

Is this the right specialist?

The clinician’s education, training, experience, and scope should match the condition and the opinion being offered.

What makes an opinion useful

The conclusion needs a reasoned medical path.

The veterans court has repeatedly emphasized that the weight of a medical opinion comes from accurate facts, a clear conclusion, and medical reasoning that connects the two. Claims-file review alone is not a substitute for analysis.

01

Who wrote it

The clinician is identified, signs the opinion, states relevant credentials, and works within a field suited to the question.

02

What was reviewed

The letter identifies the material records and history rather than making an unsupported claim that every available page was considered.

03

What condition is addressed

The diagnosis and medical question are clear enough that the reader knows exactly what the clinician is—and is not—opining about.

04

The medical conclusion

The opinion answers the relevant probability question. Familiar wording helps, but no “magic phrase” repairs an unsupported rationale.

05

The explanation

The clinician connects the history, findings, medical principles, and relevant literature to the conclusion in this veteran’s case.

06

The difficult evidence

The analysis addresses important contrary findings, alternative explanations, and aggravation when the record puts those issues in play.

Medical-opinion principles: Stefl v. Nicholson, El-Amin v. Shinseki, and the U.S. Court of Appeals for Veterans Claims opinions archive for Nieves-Rodriguez v. Peake.

PTSD needs its own map

The stressor rules change with the facts.

A PTSD claim generally involves a qualifying diagnosis, medical evidence linking current symptoms to the claimed in-service stressor, and evidence that the stressor occurred. But the way the stressor can be established differs for combat, fear of hostile activity, personal assault, and other events.

See 38 C.F.R. § 3.304(f) and VA’s current evidence guidance.

Combat and certain service circumstances

Under the applicable rule, a veteran’s statement may establish the stressor when it is consistent with the service circumstances and there is no clear and convincing evidence to the contrary.

Fear of hostile military or terrorist activity

The relaxed stressor rule has a specific requirement: a VA psychiatrist or psychologist, or one contracted by VA, must confirm that the stressor is adequate and that symptoms are related to it. A private opinion can still be evidence, but it does not by itself replace that regulatory requirement.

Personal assault

Evidence may come from sources outside service records. Requests for transfer, changes in performance, substance use, anxiety, depression, unexplained behavior changes, counseling, civilian medical records, and statements from others may be relevant markers.

The nexus letter’s job

A psychiatrist can explain diagnosis, symptom history, relevant markers, and the medical relationship to the reported stressor. The opinion should be tailored to the stressor rule and evidence actually present in the file.

A one-page preparation tool

Build the evidence map before you buy a letter.

Use this with your decision letter, C&P report, treating records, and accredited representative. The goal is to identify the one medical question that remains—not to draft your own opinion.

My VA disability evidence map

Working notes for the veteran, representative, and clinician

1. What condition am I claiming?

Use the diagnosis or condition named in the claim or decision.

2. Which claim path fits?

Direct · Secondary cause · Aggravation · Presumptive · Increase · Previously denied

3. What has VA already found in my favor?

Copy the favorable findings from the decision letter when applicable.

4. What does VA say is missing?

Use the reasons for decision and the C&P opinion—not a guess.

5. What supports the current condition?

Diagnosis, treatment records, testing, symptoms, and functional evidence.

6. What supports the service anchor?

Event, injury, disease, exposure, stressor, or existing service-connected condition.

7. Which records must the clinician review?

List the decision, examination, treatment notes, service evidence, and statements most relevant to the question.

8. What evidence cuts the other way?

Prior negative opinions, treatment gaps, other risk factors, or inconsistent facts that need a medical response.

9. The exact medical question

Example: Is the diagnosed condition at least as likely as not caused by the identified in-service event? For aggravation, ask that question separately.

Keep medical and identity information off public forums. This worksheet is for your private preparation and does not submit anything to VA or Ingleside Health.

Before paying a private provider

Check whether the gap is really medical.

A private opinion should resolve a defined evidence problem. It should not be sold as a required ticket to benefits.

  1. 01

    Ask your treating clinician.

    A provider who knows the condition and history may already be able to document what is needed.

  2. 02

    Talk with a VA-accredited representative.

    A VSO can help identify the missing element, explain the claim lane, and assist without charging for representation.

  3. 03

    Check for a presumption.

    If the law already supplies the connection, the needed evidence may be diagnosis and qualifying service rather than a private causation opinion.

  4. 04

    Attend any VA-ordered exam.

    VA may still request a C&P examination or opinion even if you submit private medical evidence.

  5. 05

    Ask what happens if the opinion is not supportable.

    A review fee should buy a real clinical review—not a promised favorable conclusion or a surprise full-letter charge.

Laura Craig, MD, board-certified psychiatrist

When the missing question is medical

Have a physician review the evidence map.

Dr. Laura Craig is a board-certified psychiatrist and former VA physician. Ingleside’s $500 first stage organizes and reviews the relevant record. It is included in the $1,500 standard service total. If she can support an opinion and you continue, the remaining balance is $1,000.

Services are currently available only to adults age 18 or older who are physically located in Illinois or Texas when professional services are provided. Continuing to intake or submitting information does not mean that a matter has been accepted. We confirm location, eligibility, conflicts, and scope before substantive professional work begins.

Begin client intake

Primary references

Read the underlying rules.

This page is an educational summary, not a substitute for the current regulation, your decision letter, or advice from an accredited representative. Sources were reviewed September 3, 2026.

Important: Ingleside Health is not affiliated with or endorsed by the U.S. Department of Veterans Affairs. This guide is general education, not medical or legal advice, claims representation, or a prediction of how VA will decide a particular claim.

This business is not endorsed or sponsored by, or affiliated with, the United States Department of Veterans Affairs or the Illinois Department of Veterans Affairs, or any federally chartered VA accredited veteran service organization. You may qualify for other veterans benefits beyond the benefits for which you are receiving services here.

Veteran and military benefits services are available free of charge from VA accredited county veteran service officers, representatives of the Illinois Department of Veterans Affairs, and the veteran service officers of federally chartered veteran service organizations. To learn more, contact these organizations or the Illinois Attorney General's Office at 1-800-382-3000.