The need for a neuronal coding scheme that is robust against the corruption of action potentials seems to support the idea of population rate coding, where the relevance of a single spike decreases proportional to the increase of population size. In order to test this intuition, we here investigate the e ciency and robustness of a population rate coding scheme in comparison to a place coding scheme using identical noise model. It turns out that the e ciency of population rate coding is substantially worse than that of place coding even if the generation or propagation of spikes are highly unreliable processes. c 2002 Elsevier Science B.V. All rights reserved.