The 50% Threshold That Determines Your VA Claim

You’ve gathered your medical records, submitted your claim, and waited months for a decision. Then you read the VA’s denial letter: “It is less likely than not that your condition is related to service.” What does that even mean? How did the VA measure “likely” versus “less likely,” and why does this phrase appear in nearly every service connection decision?

The answer lies in understanding the VA’s burden of proof standard: “at least as likely as not.” This legal threshold determines whether your claim succeeds or fails, and knowing how it works—and how medical evidence must address it—can be the difference between approval and denial.

What Does “At Least As Likely As Not” Mean?

The phrase “at least as likely as not” is the VA’s way of expressing a probability threshold of 50% or greater.

In legal terms, this is called the “burden of proof”—the level of certainty required to prove your claim. Different types of legal claims use different standards:

• Criminal cases: “Beyond a reasonable doubt” (approximately 95-99% certainty)
• Most civil cases: “Preponderance of the evidence” (more than 50%)
• VA disability claims: “At least as likely as not” (50% or greater)

The VA standard is veteran-friendly. You don’t have to prove your claim beyond a reasonable doubt or even with overwhelming certainty. You just need to show that it’s at least as probable as not that your condition is related to military service.

In practical terms:

• If there’s a 51% chance your PTSD is caused by service and 49% chance it’s not, you meet the standard. ✅
• If there’s a 50-50 chance (equal probability), you meet the standard. ✅
• If there’s a 49% chance it’s service-related and 51% chance it’s not, you don’t meet the standard. ❌

This is why the exact language used in psychiatric medical opinions is critical. Phrases like “possibly,” “could be,” or “maybe” don’t establish a 50% threshold. The psychiatric medical opinion must affirmatively state that it is “at least as likely as not” that your condition is service-related.

The 50% Threshold in VA Claims

The “at least as likely as not” standard comes from the law governing VA claims. It reflects the VA’s mission to give veterans the benefit of the doubt when evidence is evenly balanced.

Key Principle: Benefit of the Doubt

Under 38 U.S.C. § 5107(b), when evidence is in “approximate balance,” the VA must resolve reasonable doubt in favor of the veteran. This means if the evidence is roughly 50-50, the claim should be granted.

In practice, this principle means:

• You don’t need overwhelming proof
• Gaps in service medical records shouldn’t automatically lead to denial
• When psychiatric medical opinions conflict, the VA should weigh them fairly and resolve doubt in your favor

However, there’s a catch:

The benefit of the doubt only applies when evidence is approximately equal on both sides. If the VA examiner says your condition is “less likely than not” service-related, and you have no contradicting medical evidence, there’s no approximate balance—there’s just a negative opinion.

This is why veterans need strong psychiatric medical opinions that affirmatively meet the “at least as likely as not” standard. You can’t rely on benefit of the doubt if the evidence is one-sided against you.

How Medical Opinions Establish This Standard

When you submit an Independent Medical Opinion (IMO) or undergo a VA compensation and pension (C&P) examination, the physician must address the nexus between your condition and military service. The language they use matters enormously.

Language That DOES Meet the Standard:

• “It is at least as likely as not that the veteran’s condition is related to service.”
• “To a reasonable degree of medical probability, this condition was caused by military service.”
• “It is more likely than not that this condition is service-connected.”
• “Based on my review of the evidence, I conclude with greater than 50% medical probability that this condition is related to service.”

Language That DOES NOT Meet the Standard:

• “The veteran’s condition could be related to service.” ❌
• “It is possible that service contributed to this condition.” ❌
• “This condition may have been caused by military service.” ❌
• “I cannot rule out a service connection.” ❌

The difference is probability. “Could be” and “possible” suggest something less than 50%. “At least as likely as not” clearly states a 50% or greater probability.

Example: A Weak Nexus Opinion

“The veteran reports developing depression after leaving the military. It is possible that his depression is related to his service experiences. However, depression can have many causes, and I cannot definitively determine the cause in this case.”

Why This Fails: The language “possible” and “cannot definitively determine” suggests the physician is uncertain and cannot commit to a 50% probability. The VA will interpret this as not meeting the standard.

Example: A Strong Nexus Opinion

“Based on my comprehensive review of the veteran’s service records, medical history, and clinical examination, it is my opinion to a reasonable degree of medical certainty (greater than 50% probability) that the veteran’s current major depressive disorder is at least as likely as not caused by his service-connected chronic pain condition. The medical literature clearly establishes chronic pain as a significant risk factor for depression. The temporal relationship between the veteran’s pain condition and the onset of depressive symptoms, combined with the well-documented pain-depression pathway, supports this conclusion.”

Why This Succeeds: The physician explicitly states a greater than 50% probability, uses the “at least as likely as not” language, and provides medical rationale supporting the conclusion.

Common Pitfalls in Meeting This Standard

Many veterans submit medical evidence that seems supportive but doesn’t actually meet the legal threshold. Understanding these common mistakes can help you avoid them.

Pitfall #1: Treating Physician Letters That Are Too General

Your treating doctor writes: “In my opinion, this veteran’s PTSD is related to his military service.”

While this sounds positive, it doesn’t use the required “at least as likely as not” language. More importantly, if the doctor doesn’t explain why they reached this conclusion and doesn’t review service records, the VA may give the opinion little weight.

Solution: Request that psychiatric medical opinions specifically use the “at least as likely as not” language and include medical rationale with record citations.

Pitfall #2: Equivocal Statements

A C&P examiner writes: “The veteran’s PTSD could be related to his combat deployment, but it could also be due to pre-existing anxiety tendencies.”

This is an equivocal opinion—it doesn’t commit to a probability. The VA will interpret this as not meeting the 50% threshold.

Solution: Submit an Independent Medical Opinion that reviews the same evidence and provides a definitive opinion meeting the standard.

Pitfall #3: Negative VA Examinations Without Rebuttal

The VA examiner concludes: “It is less likely than not that the veteran’s depression is related to service.”

Many veterans accept this as final. It’s not. You can submit a contradicting psychiatric medical opinion from a private physician. If your IMO provides superior medical reasoning and more complete record review, the VA must weigh it against the examination.

Solution: Don’t give up after a negative C&P exam. Get a second opinion from a qualified specialist.

Pitfall #4: Lay Statements Without Medical Support

You write a statement: “I believe my anxiety disorder developed from the combat stress I experienced in Iraq.”

Lay evidence is valuable for describing symptoms and events, but veterans are not competent to provide medical nexus opinions. You can describe what happened and when symptoms began, but you need a medical professional to establish the medical connection.

Solution: Use lay statements to document facts (when symptoms started, what service events occurred), and obtain psychiatric medical opinions to establish the nexus.

Key Takeaways

• “At least as likely as not” means 50% probability or greater. This is the VA’s burden of proof for service connection claims.
• Exact language matters. Psychiatric medical opinions must use phrases like “at least as likely as not” or “more likely than not,” not “possible” or “could be.”
• Medical rationale is required. It’s not enough to state a conclusion—the physician must explain the medical reasoning supporting the 50% probability.
• The benefit of the doubt applies when evidence is balanced. If you have no positive medical evidence, you can’t rely on benefit of the doubt.
• Negative VA examinations can be countered. Submit Independent Medical Opinions that meet the standard and provide superior analysis.

How VetNexusMD Can Help

At VetNexusMD, Dr. Ronald Lee understands exactly how to craft psychiatric medical opinions that meet the VA’s “at least as likely as not” standard. Every Independent Medical Opinion Dr. Lee provides includes:

• Explicit use of VA-compliant language (“at least as likely as not,” “greater than 50% medical probability”)
• Detailed medical rationale explaining the clinical basis for the opinion
• Comprehensive review of service records, VA examinations, and treatment history
• Citations to medical literature where appropriate
• Board-certified expertise in psychiatry for mental health claims

Whether you’re filing an initial claim or appealing a denial based on a negative VA examination, Dr. Lee’s IMOs are designed to meet the legal and medical requirements the VA demands.

Learn more about our Independent Medical Opinion services or request a consultation today.

Frequently Asked Questions

What if my VA examiner used the phrase “less likely than not”?
This means the examiner concluded there is less than a 50% probability your condition is service-related. This does not automatically mean your claim is denied—you can submit contradicting medical evidence. An Independent Medical Opinion from a qualified specialist can provide a different conclusion based on more thorough record review or superior medical reasoning.

Can I use the phrase “more likely than not” instead of “at least as likely as not”?
Yes. “More likely than not” means greater than 50%, which meets the standard. Both phrases are acceptable. The key is clearly establishing a probability of 50% or higher.

Does my doctor need to use the exact phrase “at least as likely as not”?
While using the exact phrase is ideal, what matters is clearly expressing a probability of 50% or greater. Phrases like “to a reasonable degree of medical certainty,” “more likely than not,” or “with greater than 50% medical probability” can also meet the standard if properly explained.

What if two psychiatric medical opinions conflict—one says “at least as likely as not” and one says “less likely than not”?
The VA must weigh both opinions. They’ll consider the physicians’ qualifications, the thoroughness of record review, the quality of medical reasoning, and whether the opinions address all relevant evidence. A well-reasoned IMO from a board-certified specialist often carries more weight than a brief C&P examination.

Can I submit multiple psychiatric medical opinions supporting my claim?
Absolutely. If you have treating physician letters, specialist opinions, and an Independent Medical Opinion all supporting your claim, submit them all. More evidence is generally better, as long as it’s relevant and meets the “at least as likely as not” standard.

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VetNexusMD provides Independent Medical Opinions based on thorough medical record review. We do not establish doctor-patient treatment relationships or guarantee VA claim outcomes. Our service is to deliver expert psychiatric medical opinions that meet VA evidentiary standards.