Population Denominator Data Sources
The population estimates for the denominators of incidence and death rates are race-specific, ethnicity-specific, age-specific, and sex-specific county population estimates aggregated to the state or metropolitan-area level. The county population estimates that are incorporated into the National Cancer Institute’s (NCI’s) SEER*Stat software are a slight modification of the annual time series of July 1 county population estimates (by age, sex, race, and Hispanic origin) produced under a collaborative arrangement between the U.S. Bureau of the Census (Census Bureau) and CDC’s National Center for Health Statistics with support from NCI through an interagency agreement.
NCI’s modifications to the population estimates are documented in Population Estimates Used in NCI’s SEER*Stat Software. Several modifications pertain to the grouping of specific counties needed to assure the compatibility of all incidence, mortality, and population data sets. Another modification only affects population estimates for the state of Hawaii. Based on concerns that the native Hawaiian population has been vastly undercounted in previous censuses, the Epidemiology Program of the Hawaii Cancer Research Center recommended an adjustment to the populations for its state. The “Hawaii adjustment” to the Census Bureau’s estimates has the net result of reducing the estimated White population and increasing the estimated Asian and Pacific Islander population for the state. The estimates for the total population, Black population, and American Indian and Alaska Native population in Hawaii are not modified.
Population estimates used in the calculation of Puerto Rico incidence and death rates are sex-specific and age-specific, are obtained from the U.S. Census Bureau, and are not available by race or ethnicity.
In general, July 1 population estimates are used to calculate annual incidence and death rates because these estimates are considered to reflect the average population of a defined geographic area for a calendar year. However, the populations of many counties along the Gulf Coast of Louisiana, Alabama, Mississippi, and Texas were displaced in the fall of 2005 by hurricanes Katrina and Rita.
For these states, the population estimates were adjusted to account for the displacement of people in these states. The national total population estimates are not affected by these adjustments.
The majority of the evacuees from Hurricanes Katrina and Rita relocated to the following eight states: Texas, Arkansas, Louisiana, Mississippi, Alabama, Tennessee, Georgia, or Florida. The evacuee population was included in the 2005 incidence rates since all of the relocation states met the USCS publication criteria.
Similarly, to minimize the impact of Hurricane Maria that made landfall in Puerto Rico in September 2017, modified Puerto Rico population estimates obtained from the U.S. Census Bureau [PDF-332KB] are used to calculate cancer incidence rates for Puerto Rico for 2017. The population denominators were adjusted by dividing the U.S. Census Bureau’s July 1, 2017 (vintage 2021) Puerto Rico population estimate in half.