Connection to service is the link between a veteran's current medical condition and their military service: the element of a VA disability claim that answers why the VA, specifically, compensates this condition. Along with a current diagnosis and documented severity, it is one of the three elements a service-connected claim needs.

Establishing it is claims work. Medical evidence contributes, since records showing when a condition began and how it progressed bear directly on the question, and medical opinions on the link are a recognized form of evidence. But assembling the argument and presenting it to the VA belongs to the claims lane: the veteran's VA-accredited representative or VSO builds the case for connection from the evidence available.

The division of labor is worth keeping precise. Clinicians diagnose and document what a condition is and what it does. The representative argues what it is connected to. A veteran who understands which professional owns which element can evaluate any offer of help by asking which lane it actually operates in.