The value of relative organ weights

It is accepted practice in presenting organ weight data to express the results relative to the animal's body weight. The data presented suggest that in rats no benefits are obtained from this method either in reducing the variability of the data or in removing bias due to different body weights. By using simulated data it is further shown that relative weights can lead to erroneous conclusions and misinterpretation of drug effects and it is concluded that workers should present their results in absolute as opposed to relative weights.