VA disability claims are not decided on the civil 'more likely than not' standard. Under 38 U.S.C. 5107(b), when the positive and negative evidence is in approximate balance, the benefit of the doubt goes to the claimant. Practically, that means an opinion at exactly 50 percent probability is enough - which is why the wording inside a nexus letter is so important.
How the standard maps to language
Raters read opinion language as a probability statement. Approximate mapping:
- 'Is due to' / 'is caused by' - near certainty
- 'At least as likely as not' - 50 percent or greater, sufficient to grant
- 'Less likely than not' - under 50 percent, supports denial
- 'Could be related' / 'is possible' - speculative, generally given no weight
- 'Cannot be determined without resort to mere speculation' - no probative value either way
Where veterans start
Every case is different, and there is no obligation at any step. When veterans want to understand what their records actually support, these are the two most common starting points:
- Medical records review
A licensed physician reviews your records for a $250 flat fee and identifies which conditions the available evidence may support. The fee is refunded in full if nothing supportable is identified.
- Nexus letter
When the records support one, a licensed provider writes the medical opinion that addresses the link between your condition and your service or an already service-connected disability.
Why rationale beats conclusion
Two opinions using identical concluding language can be weighted very differently. The Court of Appeals for Veterans Claims has repeatedly held that the probative value of a medical opinion depends on whether the examiner reviewed the record and gave a reasoned explanation. A conclusion without rationale can be dismissed. A thorough rationale is what survives review - and it starts with a complete medical records review and ends with a properly worded nexus letter. Weak reasoning is also one of the most common reasons claims fall short.