If there is insufficient medical evidence to establish a definitive overall severity
rating, the review physician may provide a CSR. Base the CSRs on the evidence in file
and not on speculation about what missing evidence might show. However, the CSR may
include an opinion as to the potential effect of the missing documentation. While
a CSR may facilitate the POR determination, quality reviewers must exercise extreme
care when using a CSR to support a POR determination and the disability determination
is unfavorable or less than fully favorable.