The properties of pulp fibers have a strong influence on their papermaking potential. Dimensions and physical properties of fibers vary considerably. The papermaking potential of pulp is currently evaluated solely based on the mean values of fiber properties, for instance fiber length. Property distributions with the same mean value can be totally different and therefore a more suitable approach in determining pulp quality is needed. The distributions of fiber properties are likely to be more important than their mean values in controlling pulp quality, as the heterogeneity of the papermaking material is evident. Various problems associated with mean values are considered. A better understanding of characteristic distributions and their meaning in predicting paper properties can prove a significant aid in improving the quality control of pulp. (c) 2005 Elsevier B.V. All rights reserved.