Confidence Intervals in Public Health

When public health practitioners use health statistics, sometimes they are interested in the actual number of health events, but more often they use the statistics to assess the true underlying risk of a health problem in the community. Observed health statistics, that is, those counts, rates or percentages that are computed or estimated from health surveys, vital statistics registries, or other health surveillance systems, are not always an accurate reflection of the true underlying risk in the population. Observed rates can vary from sample to sample or year to year, even when the true underlying risk remains the same.