This report shows Vermont’s population counts, estimates, and percentages, by single-year of age and age groups, using the decennial census and postcensal data acquired from the Vermont Department of Health (VDH). The data are broken down by various geographies. 

Every ten years, the United States (U.S.) Census Bureau conducts a national census count using the decennial census. The U.S.Census Bureau also produces annual postcensal population estimates between the decennial census years. In cooperation with the National Center for Health Statistics (NCHS), VDH releases estimates by single year of age. 

In addition to conducting a national census count every ten years, the United States (U.S.) Census Bureau produces annual postcensal population estimates. In cooperation with the National Center for Health Statistics (NCHS), the Vermont Department of Health (VDH) produces estimates by single year of age. VDH uses county and town estimates to create estimates for non-county geographies, such as Agency of Human Services and Health Department districts.

Vermont Insights acquired the single year of age data, produced from the U.S. Census Bureau’s 2010 Decennial Census and 2011-2014 postcensal estimates, from VDH. Postcensal estimates, by single year of age, were unavailable at the town and school supervisory union (S.U.) and district (S.D.) level. Only the 2010 Decennial Census population counts for these two geographies are presented in the report.

2010 Decennial Census

The decennial census is a ‘snapshot’ of the entire population at a single point in time. The U.S. Census determines how many people reside within the country’s borders, who they are, and where they live. Every 10 years since 1790, data from the decennial census have been used to apportion seats in the U.S. House of Representatives, as mandated by the U.S. constitution. The 2010 Census established the resident population of the United States as of April 1, 2010 and reported the basic demographic characteristic of the population such as age, sex, race and ethnicity. At the state and local level, the census provides critical data for decision making on such matters as education, employment, veterans’ services, public health care, rural development, the environment, transportation, and housing. It helps communities understand how they are changing.

For more information about the 2010 Decennial Census, see the U.S. Census Bureau’s website.

2011 – 2014 Postcensal Estimates

Each year, the U.S. Census Bureau produces and publishes estimates of the population for the nation, states, counties, state/county equivalents, and Puerto Rico. The U.S. Census Bureau estimates the resident population for each year by using measures of population change. The resident population includes all people currently residing in the United States. With each annual release of population estimates, the Population Estimates program revises and updates the entire time series of estimates from April 1, 2010 to July 1 of the current year. The U.S. Census Bureau develops estimates using a cohort component method, which is derived from the demographic balancing equation:

[Population Base + Births – Deaths + Migration] = Population Estimate

The population estimate at any given time point starts with a population base (the last decennial census or the previous point in the time series), adds births, subtracts deaths, and adds net migration (both international and domestic). For more information about the postcensal estimates, see the U.S. Census Bureau’s website.

U.S. Census Bureau and Data Confidentiality

Under Title 13 of the U.S. Code, the Census Bureau must keep data they receive confidential. The Census Bureau’s Disclosure Review Board oversees the disclosure of data and assures that confidentiality is maintained through a checklist of potential security risks that must be addressed. Specifically, the Census Bureau uses techniques known as disclosure avoidance to ensure that the data they provide are modified as needed to prevent the identification of any specific individuals.

Information that could directly identify an individual, such as name, address, social security number or telephone number is never shared by the Census Bureau. However, with statistical software, the possibility of deriving a person’s identity through cross-referencing data sets with small numbers exists, so the Census Bureau takes the added measure of using disclosure avoidance techniques to prevent this.

Some census tables have small counts which, in certain cases, may identify a specific individuals. However, disclosure avoidance techniques, such as data swapping, ensure these small counts are de-identified. Because of data swapping, when users see cells with numbers like one or two, those data cells do not represent actual people but rather statistical estimates of the number of people falling into a particular set of categories. Indeed, because those numbers are so small it is very likely that the precision of such estimates is relatively low and the actual value could be zero or some number significantly higher than one or two. For more information about data swapping and disclosure avoidance techniques, see the U.S. Census Bureau’s website.

Single-year ages included ages as low as under 1-year old (aggregated) to as old as 85-years old and over for the 2010 United States (U.S.) Decennial Census and 2011 – 2015 postcensal estimate data. Vermont Insights developed an age group variable/filter to assist users with managing the data in the report displays. The age group variable consisted of three-year age groups (‘Under 1 to 2’, ‘3 to 5’, ‘6 to 8′, etc.) and one age group with several ages (’84 and over’). The ’84 and over’ age group was made up population counts from the 84-years old and 85-years old and over data points.

Population percentages for single-year ages and age groups were calculated using the following formula:

([Geography’s Population Count for Selected Age(s)] / [Geography’s Population Count for All Ages]) * 100

Population counts of 10 or less were determined to not be a privacy or confidentiality risk. Suppression was not used for these low-count cases. The U.S. Census Bureau uses disclosure avoidance techniques, such as data swapping, to ensure small counts are de-identified. See the ‘Background’ section in this report for additional details.

The 2010 United States (U.S.) Decennial Census is a recommended measure of population counts since it is a ‘snapshot’ of the entire Vermont population at a single point in time. The postcensal estimates start with a population base (the last decennial census or the previous point in the time series), adds births, subtracts deaths, and adds net migration (both international and domestic). Thus, the postcensal counts are estimates. Comparisons between the decennial census counts and postcensal estimates should occur with this limitation noted.

Postcensal estimates, by single year of age, were unavailable at the town and school supervisory union (S.U.) and district (S.D.) level.  Only the 2010 Decennial Census population counts for these two geographies are presented in the report.

Town to SU and SD mappings were done by Vermont Insights using data from Vermont’s Agency of Education. Mappings from the 2009 to 2010 school year were utilized and may not represent current town to SU and SD mappings.

Discosure avoidance techniques, such as data swapping, used by the U.S. Census Bureau can destroy analytic properties (‘true’ counts may be lost). See the ‘Background’ section in this report for additional details about the data swapping method.