Monitoring strategies should detect both acute and chronic changes within the defined potentially affected communities. Acute changes are those that can be manifested within weeks to months, such as acute disease-rate changes for malaria or respiratory infections. In contrast, chronic noncommunicable disease-rate changes for cardiovascular disorders evolve over a much longer period of time. The differences in timing, and acute versus chronic changes, help illustrate the importance of
establishing appropriate key performance indicators (KPIs).