Abstract Although quantifying animal remains in archaeological sites is best done by way of bone counts, there are several mechanisms that can cause distortions in the relative frequencies of different species. Some of these problems can be avoided by relatively minor modifications to standard methods, but the situation where bones have decayed since deposition cannot be controlled by methods currently in use. To overcome this a new technique is proposed. This involves comparing the relative frequencies of different anatomical elements across a number of sites, so that the extent of the dispersion of the frequencies of different bone classes at a site can be used as a guide to the extent of attrition there. This approach is illustrated by application to fish bones from sites in New Zealand.