A quantitative evaluation methodology for disparity maps includes the selection of an error measure. Among existing measures, the percentage of bad matched pixels is commonly used. Nevertheless, it requires an error threshold. Thus, a score of zero bad matched pixels does not necessarily imply that a disparity map is free of errors. On the other hand, we have not found publications on the evaluation process where different error measures are applied. In this paper, error measures are characterised in order to provide the bases to select a measure during the evaluation process. An analysis of the impact on results of selecting different error measures on the evaluation of disparity maps is conducted based on the presented characterisation. The evaluation results showed that there is a lack of consistency on the results achieved by considering different error measures. It has an impact on interpreting the accuracy of stereo correspondence algorithms.