As I indicated earlier, the first type of surveillance performance indicator is one which evaluates the infrastructure of our surveillance system. A surveillance system with a well-functioning infrastructure is one in which there is good completeness and timeliness of reporting from all health care providers and organizations who encounter patients with the disease, exposure, or health behavior of interest. Surveillance reports from all reporting sites are routinely reported to the surveillance system on time. The specifics of how these requirements are met vary by disease. For example, for AFP surveillance, the surveillance infrastructure is working well if at least 90% of all clinics and other reporting sites send their reports to the central health department (where all surveillance data is gathered and summarized) at the end of each month so as it ensure its arrival within the first two weeks of the following month. For conditions such as AFP where there may not be any cases reported during a particular month, this includes sending a report to the central health department to notify them that no cases were found (i.e., zero reporting). In contrast, for a disease such as measles, where the number of cases occurring each month can still be high, a surveillance system with a well-functioning infrastructure is one in which at least 80% of cases that meet a predetermined case definition based on the occurrence of selected clinical symptoms are reported to the surveillance system within 7 days of rash onset.