An analytical interpolation scheme is proposed to include correlation
effects in the local-field correction G(q,w) of the electron gas. Rigo
rous asymptotic limits of G(q,w) for large and small wave vectors and
frequencies are combined with the known frequency dependent behaviour
of G(q,w), as revealed by the time dependent HF-approximation. The cor
rect interpretation of the known sum rules in the limits of small and
large wave vectors and frequencies is of crucial importance for estima
ting the correlation contributions.