Epidemiology is a scientific discipline with sound methods of scientific inquiry at it's foundation. Epidemiology is data-driven and relies on a systematic and unbiased approach to the collection,analysis, and interpretation of data. Basic epidemiologic methods tend to rely on careful observation and use of valid comparison groups to assess whether what was observed, such as the number of cases of diseases in a particularly area during a particular time period or the frequency of an exposure among persons with disease, differs from what might be expected. However, epidemiology also draws on methods from other scientific fields, including biostatistics and Informatics, with biologic,economic, social, and behavioral sciences.