Harmful error means error by the agency in the application of its procedures which, in the absence or cure of the error, might have caused the agency to reach a conclusion different from the one reached.
Preponderance of the evidence means that degree of relevant evidence which a reasonable person, considering the record as a whole, would accept as sufficient to support a conclusion that the matter asserted is more likely to be true than not true.
Substantial evidence means that degree of relevant evidence which a reasonable person, considering the record as a whole, might accept as adequate to support a conclusion, even though other reasonable persons might disagree. This is a lower standard of proof than preponderance of the evidence.
4 C.F.R. §28.61