The relationship of differences in perceptions of two environments rated by experts and active commuters. The relationship between mean scores for the differences between perceptions of inner urban and suburban environments for the experts' and the commuters' test-retest means for 17 items. The diagonal line represents the line of identity. For both groups of raters, the mean values were either negative or positive and were therefore distributed in only two of the possible four fields of placement. The Pearson's correlation coefficient was 0.94. The symbol '○' denotes a significant difference in the size of the differences between the two groups of raters.