Life Expectancy*

Data Source

National Center for Health Statistics - Natality and Mortality Files; Census Population Estimates Program

The National Center for Health Statistics (NCHS) provides birth and death data drawn from the National Vital Statistics System (NVSS). These data are submitted to the NVSS by the vital registration systems operated in the jurisdictions legally responsible for registering vital events (i.e., births, deaths, marriages, divorces, and fetal deaths). While most calculations of mortality rates can be downloaded from CDC WONDER, calculation of the Premature Death and Life Expectancy measures requires raw data files. 

The Census Bureau’s Population Estimates Program (PEP) uses data on births, deaths, and migration to estimate population changes occurring since the most recent decennial census and produce a vintage, or annual time series of estimates. Each vintage includes the current data year and revised estimates for any earlier years since the last decennial census. Because each vintage of estimates includes all years since the most recent decennial census, the latest vintage supersedes all other estimates produced since the previous decennial census. See the Population Estimates Program methodology for statements and release notes for each vintage of population estimates.

Life Expectancy is an average

Life Expectancy measures the average number of years from birth people are expected to live, according to the current mortality experience (age-specific death rates) of the population. Life Expectancy calculations are based on the number of deaths in a given time period and the average number of people at risk of dying during that period, allowing us to compare data across counties with different population sizes.

Life Expectancy is age-adjusted

Age is a non-modifiable risk factor, and as age increases, poor health outcomes are more likely. Life Expectancy is age-adjusted in order to fairly compare counties with differing age structures.

What deaths count toward Life Expectancy?

Deaths are counted in the county where the individual lived, regardless of where the death occurred.

Some data are suppressed

A missing value is reported for counties with fewer than 5,000 population-years-at-risk in the time period.

The method for calculating Life Expectancy has changed

In the 2024 Annual Data Release, data from the Census Bureau's Population Estimates Program were used in the calculation of the denominator for this measure. In previous data releases, the denominator was calculated from the National Center for Health Statistics Bridged-Race Population Estimates; this data series was discontinued in 2023. The denominator change and updates to race categories in the 2024 Annual Data Release mean that comparisons with previous years should be made with caution. 

Caution should be used when comparing these estimates across years

Caution should be used when comparing across years due to methods changes described in the “The method for calculating Life Expectancy has changed” section.

Measure limitations

Life Expectancy includes mortality of all age groups in a population instead of focusing just on premature deaths and thus can be dominated by deaths of the elderly.¹ This could draw attention to areas with higher mortality rates among the oldest segment of the population, where there may be little that can be done to change chronic health problems that have developed over many years. However, this captures the burden of chronic disease in a population better than premature death measures.²

Furthermore, the calculation of Life Expectancy is complex and not easy to communicate. Methodologically, it can produce misleading results caused by hidden differences in age structure, is sensitive to infant and child mortality, and tends to be overestimated in small populations.^3,4

This measure can be used to track progress with some caveats. Life expectancy is a very long-term health outcome, effects on which might not be seen for years or even decades. Life Expectancy as a measure also changes much more minutely than other mortality measures due to its calculation. Coupling these matters with the three-year average provided in the Health Snapshots means that small changes, especially in small communities, may be difficult to detect.

Disaggregation means breaking data down into smaller, meaningful subgroups. Disaggregated data are often broken down by characteristics of people or where they live. Disaggregated data can reveal inequalities that are otherwise hidden. These data can be disaggregated by:

• Gender
• Race
• Subcounty Area

The Health Snapshots and downloable datasets provide Life Expectancy estimates by race. The U.S. Small-area Life Expectancy Estimates Project (USALEEP) produces estimates of life expectancy at birth for most census tracts in the United States from 2010-2015. Life expectancy estimates by gender for counties can also be accessed through the Institute for Health Metrics and Evaluation (IHME) website.

You can also use the our Mortality and Life Expectancy Calculator if you have information on the population and deaths in the geography of interest to calculate Life Expectancy estimates.

¹ Centers for Disease Control and Prevention. Premature mortality in the United States: Public health issues in the use of years of potential life lost. Morbidity and Mortality Weekly Reports (MMWR). 1986;35(suppl 2):1S-11S.

² Dranger E, Remington P. YPLL: A summary measure of premature mortality used in measuring the health of communities. Madison, WI: University of Wisconsin Population Health Institute. 2004:5(7).

³ Silcocks PB, Jenner DA, Reza R. Life expectancy as a summary of mortality in a population: Statistical considerations and suitability for use by health authorities. Journal of Epidemiology & Community Health. 2001;55(1):38-43.

⁴ Eayres D, Williams ES. Evaluation of methodologies for small area life expectancy estimation. Journal Epidemiology and Community Health. 2004;58(3):243-249.