This selects how the sampled variable's value is calculated for threshold comparison: as its absolute value at the end of the interval, or as the delta, the difference, from the previous sample. An admin chooses deltaValue for ever-increasing counters where the rate of change matters, or absoluteValue for gauges where the raw current value should be compared directly against the thresholds. For example, monitoring an interface error counter would typically use deltaValue so the alarm reflects the number of new errors per interval rather than the ever-growing cumulative total.