The Acute Gastrointestinal Illness (AGI) Study is a set of three linked surveys, with the following objectives:
•To determine the magnitude and distribution of self reported AGI in the New Zealand population;
•To estimate the burden of disease associated with AGI;
•To describe and estimate the magnitude of under-ascertainment of AGI at each stage in the national communicable disease surveillance process; and,
•To identify modifiable factors affecting under-ascertainment that, if altered, could reduce case loss throughout the AGI component of the surveillance system.