Monday, May 9, 2011

Oneida County Census Tract Maps

With the release of the 2010 decennial census data also comes the release of the new census geography for our region. Every ten years when the Census is conducted, local geography is reviewed and changes are submitted for consideration of new census tracts and block groups.

Census tracts are small, relatively permanent statistical subdivisions of a county. Census tracts usually have between 1,200 and 8,000 persons and 480 to 1,600 households. When first created, tracts are designed to be homogeneous with respect to population characteristics, economic status, and living conditions. Census tracts do not cross county boundaries. The spatial size of census tracts varies widely depending on the density of settlement. Census tract boundaries are delineated with the intention of being maintained over a long time so that statistical comparisons can be made from census to census. However, physical changes in street patterns caused by highway construction, new development, etc., may require occasional revisions; census tracts occasionally are split due to large population growth, or combined as a result of substantial population decline.

According to the U.S. Census Bureau, Dr. Walter Laidlaw originated the concept of permanent, small geographic areas as a framework for studying change from one decennial census to another in neighborhoods within New York City in 1906. For the 1910 Census, eight cities—New York, Baltimore, Boston, Chicago, Cleveland, Philadelphia, Pittsburgh, and St. Louis—delineated census tracts (then termed ‘‘districts’’) for the first time. No additional jurisdictions delineated census tracts until just prior to the 1930 Census, when an additional ten cities chose to do so.

The 1920 census data were also tabulated by tract for these cities, and Dr. Laidlaw published the figures for New York. Others followed: Chicago and Cleveland purchased and published their census tract data. By the end of the decade, 18 cities (the same eight from 1910, along with Los Angeles, Columbus, Nashville, Berkeley, Syracuse, and Yonkers) were reviewing or delineating census tracts for the 1930 census.

After 1930, the Census Bureau saw the need to standardize the delineation, review, and updating of census tracts and published the first set of census tract criteria in 1934. The goal of the criteria has remained unchanged; that is, to assure comparability and data reliability through the standardization of the population thresholds for census tracts, as well as requiring that their boundaries follow specific types of geographic features that do not change frequently.

For the 1940 census, the Census Bureau adopted the census tract as an official geographic entity to be included in data tables of the standard publications of the decennial census.  Starting with the 1960 Census, the Census Bureau assumed a greater role in promoting and coordinating the delineation, review, and update of census tracts. Census 2000 was the first decade in which census tracts were defined in all counties and the 2010 Census marks the 100th anniversary of census tracts.

Knowing where these tracts are helps policymakers, business leaders and the public plan for our future. Below are three maps, one for the Oneida County as a whole, and then two separate maps, one each for Utica and Rome, showing the tract level geography that will be in place for the next 10 years.

Utica Area Tracts (2010)

Rome Area Tracts (2010)
Oneida County Tracts (2010)

Friday, April 8, 2011

Minority Distribution Maps

Minority population distributions have changed over time, partly because we have seen a growth in minority inflow to the region, and partly because of changes in race category definitions within the Census.

These 3 maps show the changes between the 1990, 2000, and 2010 censuses for the City of Utica and the surrounding area.

1990 Minority Distribution

2000 Minority Distribution

2010 Minority Distribution

Several things should be noted:

  1. Between 1990 and 2000 the Census changed how it recorded race data. No longer were people restricted to a single race category, but could select multiple races.
  2. Note how concentrated the areas with at least 25% of the population being of minority background was in the center of Utica. By 2000 the area had grown substantially to a large area surrounding that same core; by 2010 the minority population had expanded considerably into the West Utica neighborhoods.
  3. North Utica sees considerable minority growth in 2000; South Utica sees it's minority populations expand particularly in the last decade.

Friday, April 1, 2011

The Three Pillars of Census Based Data

When most people hear the words "Census Bureau" they only think of one thing - "the" census. Of course what they really mean is the "decennial" census, being that survey we all take once every 10 years as part of our constitutional duties. In reality the Census Bureau conducts a slew of surveys covering a wide range of topics. However, there are three that are interrelated that I want to review here. Because they are often confused with one another, it is important to understand how they differ and what that difference means for the data user.

The first is the data product mentioned above - the decennial census. The decennial census is conducted once every 10 years, administered officially on April 1 of any year ending in a zero. Historically the decennial census has been used to capture not just population counts but also to help flesh out the character of the people living in the country. It did this by offering two forms - a short form and a long form.

Understanding the American Communities Survey

In the past, every ten years the Census Bureau conducted our decennial census to provide information to Congress and policymakers about the country. This was done through two forms – the short form (with only 7 or 8 basic questions) and the long form (which had lots of questions on everything from income to education). 

Beginning in 2010, the decennial census will ONLY be done with the short form. In place of the long form, a new tool called the American Communities Survey was fully implemented in 2005. The American Community Survey (ACS) is a nationwide survey designed to provide communities a fresh look at how they are changing. 

With the ACS, the Census Bureau now collects and produces population and housing information every year, instead of every ten years. About three million housing unit addresses are sampled each year throughout the United States and Puerto Rico to produce this data. 

Beginning with the 2005 ACS (and continuing every year thereafter), a variety of demographic, social, economic and housing data for each year was made available for geographic areas with a population of 65,000 or more. These are called the “1 Year Estimates” – they are based on a single year’s sampling of our local population. Because these “1 Year Estimates” were only released for communities with populations of 65,000 or more, in our region this only covered Oneida County as a whole.

In 2008, however, the ACS released its first multi-year estimates based on ACS data collected from 2005 through 2007. These are called the “3 Year Estimates”. The “3 Year Estimates” of demographic, social, economic and housing characteristics are available for geographic areas with a population of 20,000 or more. For our region, this now means data are available for Oneida County, Herkimer County, Utica, Rome and the Town of New Hartford. 

This past December the Census released “5 Year Estimates”.  With their release, data is now available for ALL levels of geography, regardless of population size. These data cover the sample period of 2005 to 2009.

The 3-year and 5-year estimates require slightly different thinking about the data they contain. These 3-year estimates are called “period estimates”. So when discussing the child poverty data, for example, the best way to characterize this information would be along the following lines: “The child poverty rate for Oneida County over the period 2005 to 2007 was 'X' percent.”  These are NOT an average of 3 or 5 individual years; they are the average of a sample taken over 3 or 5 years.

Comparing the 3-year and 5 year estimates to other Census measures is possible, but with some caveats. Generally the following are good guidelines:

  1. If comparing across geographic areas (like between two towns or two counties), make sure you are comparing apples to apples.  That is, compare 1-year estimates to 1-year estimates, or 3-year estimates to 3-year estimates, and 5 year to 5 year estimates. DO NOT compare one-year estimates with three-year estimates across geographies.
  1. If comparing data for a single area (like just one town or one county to itself) over time, this can be done but it must be done with caution. Comparing the 2000 Census for Herkimer County to the 2005-2007 period estimate, for example, in Herkimer County is acceptable, but keep in mind there can  problems with differences in residency rules, reference period differences, and question wording changes.
  1. If you are more interested in current data, 1-year or 3 year estimates are the better source to use; if precision is more important, then use the 5-year estimates. The five year estimates represent a larger sample size over a longer period of time so they have more reliability, especially for smaller areas.
A good source for what is and isn’t comparable when using the ACS data sets is found here or by going to the Census Bureau website at: . The site url is case sensitive so be sure to use lower and upper case letters as in the address listed for the site.

Thursday, March 31, 2011

Mean Center of Our Country

The U.S. mean center of population, as of April 1, 2010, is near Plato, Mo., an incorporated village in Texas County. The U.S. Census Bureau calculated this point as the place where an imaginary, flat, weightless and rigid map of the United States would balance perfectly if all 308,745,538 residents counted in the 2010 Census were of identical weight.

Ever since Chestertown, Md., was determined to be the center of population after the first census was conducted in 1790, the center of population has told the story of America, illustrating how we've grown as a nation. It follows a trail across the country ─ across Maryland, Virginia, West Virginia, Ohio, Kentucky, Indiana and Missouri ─ that reflects our history of settling the frontier, manifest destiny, waves of immigration and regional migration.

The Census Bureau will install a commemorative "geodetic control mark" at a site near the official coordinates during a dedication ceremony in April 2011. This survey disc will be used by satellites and land surveyors to conduct scientific surveys to generate precise position data that serve as the foundation for accurate mapping and charting in America.

Wednesday, March 30, 2011

Housing Unit Changes 2000-2010

Of the few thing released in the 2010 PL94-171 data is information on housing units - namely the the number of total housing units, the number occupied, and the number vacant. Below is a table showing the counts from the Census 2000, Census 2010, and the changes within each municipality.

Only three communities saw a decline in the number of housing units (Bridgewater, Rome and Utica). As a whole, both counties saw increases of more than 1,300 new housing units identified in this year's census compared to the 2000 Census.

Census 2010 Data Has Arrived !

Finally, after what seems like a decade (oh HAS been ten years hasn't it?) Herkimer and Oneida Counties have new decennial census data ! The data, released on March 24th, represents the PL 94-171 data used for redistricting purposes. It is a limited release of data but includes four components of the 2010 Census: population, racial breakdowns, voting age racial breakdowns, and housing occupancy. More data from the 2010 Census will be released in May.

In the meantime, this data gives us our first look at what the decade has wrought to our region in the last decade. the news appears to be much more positive than the Census Estimates program would have led us to believe.

To begin with, Herkimer County's population actually has grown ! And in Oneida County, while the population has dropped slightly, the overall loss is less than 600 people. Below are two tables with historical population counts for Herkimer and Oneida Counties, including the 2010 Census !


This represents our first post to the Herkimer and Oneida Counties  Census Data Affiliate Blog.