The Census came to town – Do we know what we know?

The Census came to town –Do we know what we know?Christopher BriemUniversity Center for Social and Urban ResearchUniversity of Pittsburgh

The Census came and went –Do we know what we know?Christopher BriemUniversity Center for Social and Urban ResearchUniversity of Pittsburgh

This Presentation• Living without the long form census• What the American CommunitySurvey tells us….. and what it doesnot• Pittsburgh Neighborhood Profiles• Data still to come

The Basics from Census 2000• Short Form– Survey of 100% of the population– Questions about the basic demographiccharacteristics• Long Form– Sample of one in six housing units(approximately 17% sample)– Basic demographic questions– Virtually all economic questions

The Basics from Census 2010• Short Form– Survey of 100% of the population– Questions about the basic demographiccharacteristics only• Long Form– Sample of one in six housing units(approximately 17% sample)– Basic demographic questions– Virtually all economic questions

American Community Survey• A nationwide, continuous monthly survey• Samples 3 million addresses per year or250,000 addresses each month.• Data will be released annually forcommunities of 65,000 or more people• Profiles available for 3 year period averagesfor communities with fewer than 65,000people but more than 20,000• Smaller places (

Why ACS?• Disadvantages include– Smaller sample frame – larger sample errors– Multiple reporting periods– Not perfectly consistent with decennial dataproducts• Advantages include:– No longer 10 year gap in data– Professional data collection should reduce selfreportingerrors– Cost of long form for entire population

Neighborhood data

Comparing ACS and Decennial Census• Decennial census counts everyone• Decennial references a single point in time(April 1)• ACS sample size is smaller – 1 in 8• ACS data is supplied with ―margin oferror‖• ACS data is an average over 1, 3, or 5 years• ACS should be used to reference―characteristics‖, not absolute counts

Just remember…• Best to compare similar estimates:– Example: Compare 3-year estimates to 3-year estimates• Be careful about comparing over time:– Do not compare overlapping estimates (e.g.,2005-2007 & 2006-2008)– Do compare 2005-2007 & 2008-2010• Which estimate you choose can changethe story!

Point in time versus Period data• Decennial data is point in time—April 1• ACS is period data– Data collected almost daily– Information is anchored to day on whichsample housing unit was interviewed. So,―last 12 months‖ depends on when theinterview occurs.• Important when comparing data like:employment, income, and studentenrollment.

What Data is available now:• Census 2010 Redistricting Data (decennial)– Total Population, by race, and broken down by votingage population• ACS 2005-2009 Data– Via Census Factfinder for tract level data– Block Group Data available via Census/FTP– UCSUR neighborhood profiles now available• Group Quarters Data (decennial)• Census 2010 Age Detail (just released)

Decennial Population by NeighborhoodNeighborhood 2000 2010 ChangeGarfield 5,384 3,675 -1,709 -31.7%Northview Heights 2,565 1,214 -1,351 -52.7%Homewood North 4,620 3,280 -1,340 -29.0%Golden Triangle* 4,874 3,629 -1,245 -25.5%Saint Clair 1,435 209 -1,226 -85.4%Homewood South 3,549 2,344 -1,205 -34.0%Brookline 14,320 13,214 -1,106 -7.7%Perry South 5,244 4,145 -1,099 -21.0%East Liberty 6,937 5,869 -1,068 -15.4%Hazelwood 5,334 4,317 -1,017 -19.1%

UCSUR Profiles:• ACS 2005-2009 Data• All 90 Neighborhoods• „Meta‟ Neighborhoods• Selected Tables• Online this morning/A few copies here

Some ACS-Decennial Census DifferencesDecennial ACSNeighborhood 2010 2005-2009 DifferenceSquirrel Hill North 11,363 12,793 -1,430Brookline 13,214 14,462 -1,248Brighton Heights 7,247 8,366 -1,119Saint Clair 209 1,064 -855Bloomfield 8,442 9,202 -760Fairywood 1,002 400 602Golden Triangle* 3,629 2,856 773Marshall-Shade. 6,043 4,868 1,175Central Oakland 6,086 4,794 1,292North Oakland 10,551 8,945 1,606

Know your neighborhood• ACS sample errors can significantly changemetrics for neighborhoods/smallareas/small groups.• Different data sources may appear verydifferent (decennial vs. ACS)• Some errors happen (Downtown 2000example)

Coming in the future• This Summer: Interactive Neighborhood Datato go with UCSUR profiles and other Decennialdata• Through 2011: From Census Bureau: Morebreakouts of 2010 Decennial Census data.• Fall 2011: ACS 2006-2010 Data (based on newgeography and population controls!!)

Looking for data?• Census Factfinder:http://factfinder.census.gov• Our Pittsburgh Urban Blog:http://www.ucsur.pitt.edu/thepub.php• PNCIS -> “Neighborhood reports”http://www.ucsur.pitt.edu/pncis.php