Standard Populations (Millions) for Age-Adjustment

Standard populations, often referred to as standard millions, are the age distributions used as weights to create age-adjusted statistics. Standard population data is distributed through the SEER*Stat software. SEER also provides U.S. Population Data, which can be used for analyses with SEER*Stat or other software.

Updates to Age Adjustment for the 85+ Population

Starting with the November 2024 submission, the default age groups used for age standardization have been updated to 20 groups, with ages 85+ divided into 85–89 and 90+, or into single-year ages (85, 86, 87, 88, 89, and 90+) when single-year data is available. The standard populations used for age adjustment remain unchanged, continuing to rely on the 2000 U.S. population estimates from the Census P25-1130 (PDF)¹ series, introduced with the November 2004 SEER submission (covering diagnoses through 2002) see below.

As life expectancy increases, the 85+ population has grown larger and more diverse, with significant variations in health and mortality risks. Dividing this group into detailed subcategories improves the accuracy of age-standardized statistics and enhances comparisons between populations with varying 85+ demographics.

Prior Changes to Standard Populations and Age Standardization

Before 2004, SEER used "standard millions" (rounded to the nearest million) derived from Census P25-1130 series estimates for 5-year age groups. However, to improve the accuracy of age standardization and enable age-adjusting by single ages, SEER transitioned to using unrounded standard populations with the November 2004 data submission (covering diagnoses through 2002).

Using unrounded standard populations allows for precise calculations of standard population values for 5-year age groups by summing single-year standard populations. This approach also supports more granular age standardization using single-year or custom age groupings. In contrast, the use of "standard millions" poses challenges—as for example creating standard millions for single ages from the grouped standard millions. For further details, refer to the discussion on the 2000 U.S. Standard Population vs. Standard Million.

Standard Population Files

The standard population data files contain the following data:

• U.S. Standards (1940, 1950, 1960, 1970, 1980, 1990, 2000)
• Canadian Standards (1991, 1996, 2011, 2021)
• European (Scandinavian 1960) Standard²
• European (EU-27 plus EFTA 2011-2030) Standard
• World (Segi 1960) Standard²
• World (WHO 2000-2025) Standard²

View the Standard Populations

• Standard Populations - 20 Age Groups (0, 1-4, 5-9, 10-14, ..., 85-89, 90+)
• Standard Populations - 19 Age Groups (0, 1-4, 5-9, 10-14, ..., 85+)
• Standard Populations - Single Ages

¹ Day, Jennifer Cheeseman, Population Projections of the United States by Age, Sex, Race, and Hispanic Origin: 1995 to 2050, U.S. Bureau of the Census, Current Population Reports, P25-1130, U.S. Government Printing Office, Washington, DC, 1996. (View PDF (PDF))

² The labels for these standards were updated on November 1, 2012 to clarify which standards they correspond to, but the data did not change. Documentation for the standards are in the World Health Organization's publication, Discussion Paper 31: Age Standardization of Rates: A New WHO Standard