In a previous blog posting I discussed evidence in general and the benefit-of-the-doubt rule. I also mentioned the three essential facts that must be proven in a service-connection claim: that there was an injury or first manifestation of disease in service, there is a current disability, and the disability is causally related to the event in service. Medical evidence is crucial to two of these three elements. Unless a disability is so obvious that a lay person can discern it, an amputated limb for example, evidence from a medical provider of some type is necessary to establish that there is a physical or mental condition that is disabling. On the important question of medical causation of a disability, whether the current condition is related to something that occurred in service, the evidence is usually in the form of expert opinion from a doctor or other health-care provider. Even if service connection is established, in order to obtain a higher rating for the condition, there must be medical evidence of the severity of the disability.
In the old days, panels of the Board of Veterans’ Appeals had at least one doctor on them and they evaluated medical issues, but under present law the VA is not permitted to decide medical questions based on its own judgment without expert opinion to support its decision. Precisely because this evidence must generally come from a medical professional, it is often the most difficult aspect of a claim for veterans to establish.

Sources of medical evidence
It should be noted that medical opinions do not necessarily have to come from doctors. While the strongest opinion might come from a specialist in a particular area, e.g. a psychiatrist rather than a family doctor concerning a mental condition, anyone with medical training can render an opinion. Thus, PTSD diagnoses have been based on the opinions of social workers or trauma counselors who are not MDs. Depending on the issue, a nurse could be at least as persuasive as a doctor, regarding, say, what hospital treatment would have been.
Diagnosis of a disability and the severity of impairment caused by that disability can frequently be proven by medical records from health care providers who have treated the claimant. Sometimes a treating physician must be asked specifically to comment on the subject, but he or she is usually willing to do so. More challenging, sometimes, is obtaining the opinion that a present condition is related to an event in service, what VA law calls a “nexus” opinion. This type of opinion statement is rather specialized and must be written in a certain way.
Some medical cause-and-effect relationships are quite apparent: the damage done by a gunshot wound, the scar caused by a laceration, the bone fracture resulting from a trauma. But many such relationships are less clear, such as the relationship between a trauma to a joint and development of arthritis in the joint many years later, or the connection between some frightening or stressful experience in service and later manifestation of mental disease. These relationships are determined through the judgment of medically-trained people.
Medical causation is often a matter of probabilities. It cannot be determined with certainty, for example, whether a back injury in service caused or hastened the onset of degenerative arthritis in the back many years later, but doctors will often be able to offer an opinion as to the likelihood of a relationship. Thus, one doctor might be of the opinion that too much time has passed for an isolated injury in service to have been the likely cause of arthritis, while another doctor may believe that the trauma to the back made the joints more susceptible to degeneration and thus contributed to causing the arthritis. To support the claim, the veteran needs an opinion that there is a relation to service, at least as likely as not.
It is because of the benefit-of-the-doubt rule that medical opinion reports in veterans cases contain language using some variation of the phrase “as likely as not.” As long as the probability of causal relation is 50-50, that is, “as likely as not,” the evidence is balanced, and the benefit-of-the-doubt rule tips the decision in the veteran’s favor. That is why you will so often see medical opinions stated in terms of “as likely as not” or something similar.
Doctors familiar with the VA system usually have some notion about how to phrase opinions in this way, but doctors who have not had experience with the VA claims system will not. Indeed, many doctors have some acquaintance with a significantly different standard used in civil litigation: “to a reasonable degree of medical certainty.” Because veterans need only prove elements of their claims as likely as not, i.e. to a 50-50 probability, they do not have to show medical “certainty” to a reasonable degree, which is a more exacting standard. When this is fully explained, a doctor will sometimes be able to see her way clear to offer an opinion that she would not have been able to offer under the stricter standard. That is, a doctor may be uncomfortable, based on existing medical science and literature, saying that Agent Orange exposure caused a particular cancer to a reasonable degree of medical certainty, but may not be so hesitant to say it is at least as likely as not that the defoliant caused the cancer.
It is also important for doctors writing opinions to support veterans’ claims to bear in mind that something does not have to be a sole cause to be related sufficiently to establish service connection. If the in-service event or condition was a contributing factor to a later disability, that is enough to sustain the claim.
The court that reviews VA decisions has recently expounded more detail about how medical opinions are to be considered by VA. The essential features are that the provider expressing the opinion must have had the appropriate data available, must state clear conclusions based on that data, and must give a reasoned explanation linking the conclusions to the data. Thus, any opinion obtained in support of a claim should contain a statement as to what was reviewed, whether a physical examination was done, what the opinion is, and what the rationale for the opinion is.

NEXT TIME: How VA gets around the benefit-of-the-doubt rule and what you can do to counter this.