Mean absolute relative difference MARD

In addition, all the paired points (n) including the concentrations measured from the glucose sensor, [glucose] sensor, and the reference glucose measurement, [gluco-se reference, in the correlation plot are used to calculate the overall mean absolute relative difference (MARD). The median MARD is the median relative difference among all the measured values. 

Mean absolute difference (MAD) and mean absolute relative difference (MARD) - MAD and MARD quantify the performance in an entire data set within a single value. MARD is a good metric for comparing multiple systems in a single study, but is not useful itself to describe system quality [187, 193]. 

Figure 3.2 The effect of prolonged subcutaneous implantation on biosensor function. Blood glucose values shown in solid circles and glucose sensor values in the continuous lines. The early study (top panel), but not the late study (bottom), shows excellent sensor accuracy and minimal lag between blood glucose and sensed glucose values. MARD (mean absolute relative difference) refers to a sensor accuracy metric. EGA refers to the Clarke error grid analysis accuracy metric.

MAD, mean absolute difference MARD, mean absolute relative difference SD, standard deviation SE, standard error SRE standard relative error. 

The different manufacturers publish their own results in their user manuals. Mean absolute relative difference and bias results from the three manufacturers are shown in Table 5.2. The MARD measures indicates the average difference while the direction of the difference and the bias indicates if the differences are uniform or skewed to positive or negative values. The Clarke error grid analysis for the three manufacturers (Table 5.3) shows a wide difference in A zone results between the... 

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