Space-distortion has been recognised as an important factor in selection of a classificatory fusion strategy but has not been considered in depth. This paper suggests that two separable phenomena are present. Analysis shows that the group-average strategy is free from both forms and that the flexible strategy is not group-size-dependent. While use of the centroid and incremental sum of squares strategies has been regarded as dubious with other than distance measures and squared Euclidean distance, it is argued that both can be viewed as formulated algebraically and then retain their established space-distortion properties.