Sensitivity and Appropriateness:
Sensitivity refers to the capability to detect changes or differences when they to occur. Often, multimodel measurements are made because of variations in sensitivity e.g. some fear-reduction research has shown that changes in subjective feelings are not necessarily accompanied by changes in elevated heart rate. Heart rate, therefore, may not be sensitive enough to demonstrate change as a result of some interventions particularly if it is observed immediately after administration of the experimental variable. Therefore, it is necessary to include different 'measures to estimate fear.
Appropriateness refers to whether or not the measure can be used for a particular target population. It also refers to the extent to which the target population can meet demands of the instrument, such as understanding and following the directions and having the physical stamina and motivation to complete the measure. If a measure is inappropriate it could measure wrongly.