  We discuss surface roughness effects on the conduction of electrons in metals
using both the quantal Kubo-Greenwood formalism and the semi-classical
Fuchs-Sondheimer method. The main purpose here is to compare these methods and
clarify a few subtle conceptual issues. One of such issues is concerned with
the conditions under which the broken translation symmetry along a rough
surface may be restored. This symmetry has often been presumed in existing work
but not always with proper justifications. Another one relates to the physical
meaning of a phenomenological parameter (denoted by $p$) intuitively introduced
in the semi-classical theory. This parameter, called the specularity parameter
or sometimes the \textit{Fuchs} parameter, plays an important role in the
experimental studies of surface roughness but has so far lacked a rigorous
microscopic definition. The third issue arises as to the domain of validity for
the electrical conductivity obtained in those methods. A misplacement of the
domain may have resulted in erroneous analysis of surface effects in a variety
of electrodynamic phenomena including surface plasma waves.
