Both measures involve a comparison of the extent of large and small vertical pen-strokes. However, the variability between the writing of different individuals relative to the variability observed within any one individual's writing was greater in the case of d-proportion than in the case of el-ratio. For the purposes of forensic handwriting comparison, d-proportion may be considered potentially the better feature. If measurements based on physical continua are to be seriously considered as candidate features in computer-aided comparisons of handwriting, the present result suggests that it will be important to take account of the particular letter within which the pen-strokes appear. (Publisher abstract)