However, if you provide care based on a patient's felt need, then you have left the system open to abuse because the patient's will be using the system even though there is no clinical need to treat or see the patient. The reason for measuring need in a population can play an important role in how need is measured. There are three defined reasons to measure need. The evaluation method uses a metric that is comparative based. This method may compare one population to another or it may compare the same population to itself at a previous point in time.
Estimation is used to decide how many resources are needed for a given population.
The meter used in this method relates statistics to population standards. Priority-setting is used to define what diseases or situations are the most important. Social, ethical, and moral issues determine the meter used with this method because a society defines what is important and what is not important.