Ready for the next step? Understand medical nexus evidence
Why the wording matters
A compensation and pension (C&P) examiner may use this phrase when answering whether your current condition is related to a service event. A private clinician may use it in a nexus letter. A favorable answer helps address that particular medical question; VA still decides the claim from the whole record.
Example: In a hypothetical knee claim, an opinion linking the current condition to an injury during service addresses the connection. It does not, by itself, establish every fact about the injury, resolve all conflicting evidence, or determine the disability percentage. Claim Raven's nexus-letter guide explains how that opinion fits into a claim.
It does not require an exact numerical tie
Older forms and many online explanations describe the phrase as a 50 percent or greater probability. That is useful shorthand, but it can suggest a precision that weighing evidence does not have. A clinician is not expected to calculate a statistical probability for your individual claim.
The Federal Circuit explained in Lynch v. McDonough that approximate balance includes evidence that is nearly equal, not just an exact tie. The benefit-of-the-doubt rule does not apply when the evidence persuasively favors one side over the other.
Current VA forms use the wording “approximately balanced or nearly equal” when explaining this medical-opinion standard. One official example is the diabetes Disability Benefits Questionnaire. This wording was checked September 25, 2026.
The medical opinion and the legal rule have different jobs
Under 38 U.S.C. 5107, VA gives the claimant the benefit of the doubt when the positive and negative evidence concerning a material issue is approximately balanced. 38 CFR 3.102 explains that reasonable doubt must arise from the evidence rather than speculation or a remote possibility.
The clinician supplies medical evidence. The VA decision-maker weighs that evidence together with the other relevant records and statements. A favorable opinion is therefore evidence supporting an issue, not an instruction requiring VA to award benefits regardless of everything else.
Similarly, “less likely than not” is an unfavorable answer to the medical question asked. It is not a final denial letter. Read the explanation, the records considered, and the exact question before deciding what is missing.
What makes an opinion useful
Read past the conclusion. A useful opinion should make these points understandable:
- The condition and connection being evaluated. Is the question direct service connection, causation by another disability, or aggravation by another disability?
- The relevant facts. Which treatment entries, symptoms, service events, and medical history support the analysis?
- The medical explanation. Why do those facts support or weaken the proposed connection, including relevant alternative explanations?
- The clinician's qualifications. Is the person qualified to address this medical question? 38 CFR 3.159(a)(1) defines competent medical evidence in terms of education, training, or experience.
Example: A hypothetical letter saying only that knee pain “could be related” to service leaves the likelihood and reasoning unclear. An opinion that addresses the documented injury, later symptoms, examination findings, and other potential causes gives VA more to evaluate. Neither example means a clinician should reach a favorable conclusion unsupported by the records.
Use the nexus-letter explanation to understand the document's purpose. A privately purchased letter is not required in every claim; VA may obtain an opinion through its C&P examination process.
Common mistakes
- Treating the phrase as a guaranteed approval. Other required facts or conflicting evidence may still need attention.
- Demanding medical certainty. The VA standard is not proof beyond every possible doubt.
- Counting opinions instead of reading them. Two short favorable conclusions do not automatically outweigh one well-supported unfavorable analysis, or vice versa.
- Confusing a possible connection with an approximately balanced one. “Could be” may identify a possibility without answering the requested likelihood question.
- Asking only about causation in a secondary claim. An opinion about whether one disability caused another may leave a separate aggravation question unanswered.
Questions veterans ask
Does this mean a 50 percent disability rating?
No. It concerns evidence supporting a connection or another medical issue. The rating percentage concerns the severity of a service-connected disability under the applicable criteria.
Must my doctor use these exact words?
The words clearly communicate the standard, but the substance and supporting explanation matter. If an opinion is ambiguous, ask the clinician to clarify what the evidence supports, without asking them to change an honest medical conclusion.
What if VA denies the claim despite a favorable opinion?
Read the decision's reasons and favorable findings. Determine whether VA disputed the medical connection, another required fact, or the opinion's reasoning. Then compare the decision-review options with the actual issue before submitting more evidence.
Claim Raven explains VA rules in plain English so you can work your own claim. It is not legal advice, and Claim Raven is not affiliated with the Department of Veterans Affairs. Browse every VA term.