Dose reconstruction provides information to estimate past contaminant releases and potential public exposures, which in turn can be used to determine the feasibility of epidemiologic studies. An epidemiologic study identifies the types and frequencies of specific diseases in a population group. For example, a cancer study involves collecting data on the number of residents who have developed different types of cancer. The Colorado Central Cancer Registry, for instance, compiled data on cancers statewide to allow for an accurate comparison of cancer incidence in the Rocky Flats Plant area with other regions of Colorado. Just because disease rates can be computed for areas near nuclear facilities does not mean they can be used to show whether or not the facility was responsible for causing disease.
Scientists require fairly stringent evidence for such conclusions.
The disease rates would then be examined statistically to see if they are related to the magnitude of exposure. Two studies of cancer incidence in communities near Rocky Flats were published in the 1980s. The studies reached opposite conclusions about the relation between cancer incidence and estimates of plutonium concentrations around the plant. A problem with both studies is the small number of measurements of plutonium in soil that were used to determine exposure from Rocky Flats. It is not clear that those measurements accurately reflected the cumulative history of plutonium releases from the plant.