Estimates of the burden of acute gastroenteritis (AGE) are difficult to compare across research due to different definitions of the condition. By examining databases for studies that collected daily observations of AGE symptoms, researchers were able to identify AGE criteria used in prospective, community-based childhood cohort studies. The definitions of diseases and the refractory periods were retrieved. Using defined AGE criteria and the World Health Organization definition for diarrhea, data from the Australian community-based Observational Research in Childhood Infectious Diseases birth cohort were utilized to quantify AGE incidence and duration. There are eight different AGE definitions.

All of them had loose stools, and seven of them had vomiting as a symptom. The refractory interval between episodes ranged from one to twenty-one days. When the AGE incidence was applied to the Observational Research in Childhood Infectious Diseases dataset, it varied from 0.8 to 2.6 occurrences per child-year-at-risk, a threefold relative difference. Direct comparisons of rates from various cohorts are only possible if an agreed-upon definition of AGE is used.