Fig. 4

Shewhart chart of a student measuring EMD (N = 30). In each measurement series, interrater EMD differences (average of two series by a senior rater – student) are plotted. Error bars cover the 0.1th to 99.9th interpercentile range (IPR) of these interrater differences, according to the control limits given by the senior rater’s intrarater IPR (dotted lines). A bold solid line indicates the median value of the senior rater’s intrarater differences. Median interrater differences are linked across the four measurement series by a thin solid line