America is changing so is the Census. 1790 Decennial Census 1850 Population Characteristics

1. America is changing so is the Census. 1790 Decennial Census 1850 Population Characteristics 1940 Introduction of sampling. 1960 Mailout/Mailback 1980 Block Data 1990 TIGER/LINE files 2000 Paid Promotional Campaign 2006 American Community Survey 2010 – Short-form only.

2. Decennial Census • In Census 2000, the census used two forms • “Long” Form – Collected the same information as the short form but also collected more in-depth information such as income, education, and language spoken at home • “Short” Form – Asked for basic demographic and housing information, such as age, sex, race, how many people lived in the housing unit, and if the housing unit was owned or rented • Only a small portion of the population, called a sample, received the long form.

3. 2010 Census and American Community Survey • 2010 Census will focus on counting the U. S. population • The sample data are now collected in the ACS • Puerto Rico is the only U. S. territory where the ACS is conducted • 2010 Census will have a long form for U. S. territories such as Guam and U. S. Virgin Islands • Same “short form” questions on the ACS

4. The content collected by the American Community Survey can be grouped into four main types of characteristics – social, economic, housing, and demographic. Let’s take a closer look at the type of information each of these categories contain.

5. Education Marital Status Fertility Grandparents Veterans Disability Status Place of Residence 1-year ago Citizenship Year of Entry Language Spoken at Home Ancestry / Tribal Affiliation American Community Survey: Social Characteristics

6. American Community Survey: Demographic Characteristics • Sex • Age • Race • Hispanic Origin

7. American Community Survey: Economic Characteristics • Income • Benefits • Employment Status • Occupation • Industry • Commuting to Work • Place of Work

8. American Community Survey: Housing Characteristics • Tenure • Occupancy and Structure • Housing Value • Taxes and Insurance • Utilities • Mortgage / Monthly Rent

9. American Community Survey: 2008 Content Changes • Three new questions • Health Insurance Coverage • Veteran’s Service-related Disability • Marital History • Deletion of one question 1. Time and main reason for staying at the address • Changes in some wording and format

10. Health Insurance Coverage

11. Veteran’s Service-related Disability

12. Marital History

13. American Community Survey: Methodology • Sample includes about 3 million addresses each year • Three models of data collection: 1. Mail 2. Phone 3. Personal Visit • Data are collected continuously throughout the year • High levels of quality have been demonstrated

14. American Community Survey: Target Population • Resident population of the United States and Puerto Rico • Living in housing units and group quarters • Current residents at the selected addresses • “Two month” rule

15. American Community Survey: Period Estimates • ACS estimates are period estimates describing the average characteristics over a specified period • Contrast with point-in-time estimates that describe the characteristics of an area on a specific date • 1-year, 3-year, and 5-year estimates will be released for geographic areas that meet specific population thresholds

16. Most ACS questions do not stipulate a period of time that should be referenced Interpretation is yearly average since the data are collected each month and averaged across months Questions with no specific reference period

17. Other questions specify a period of time relative to the date of interview Interpretation is still a yearly average but covering a slightly different period of time than the calendar year Questions with a specific reference period relative to interview date

18. American Community Survey: Data Products Release Schedule

20. American Community Survey: Data Products • Profiles • Data Profiles • Narrative Profiles • Comparison Profiles • Selected Population Profiles • Tables • Detailed Tables • Subject Tables • Ranking Tables • Geographic Comparison Tables • Thematic Maps • Public Use Microdata Sample (PUMS) Files

21. ACS and Sampling Error • Definition of sampling error • Measures associated with sampling error • Margin of error • Standard error • Confidence intervals • Coefficient of variation • How to use measures associated with sampling error • Non-sampling error • Population controls

22. What is Sampling Error? Definition The uncertainty associated with an estimate that is based on data gathered from a sample of the populationrather than the full population

23. Interpreting Margin of Error • Means that a data user can be 90 percent certain that the estimate and the population value differ by no more than the value of the MOE • MOE can help data users assess the reliability of an estimate • MOE can help data users avoid misinterpreting small differences between estimates as significant

24. Test of Statistical Significance Definition: A test to determine if it is unlikely that something has occurred by chance A “statistically significant difference” means there is statistical evidence that there is a difference

25. What is Non-Sampling Error? Definition: Any error affecting a survey or census estimate apart from sampling error Occurs in complete censuses as well as in sample surveys

26. Types of Non-Sampling Error • Non-Response Error • Response Error • Processing Error • Coverage Error

27. What Have We Learned? • All surveys have sampling and non-sampling error • Four key measures of sampling error are margin of error, confidence interval, standard error, and coefficient of variation • Measures of sampling error provide important information about the reliability of ACS estimates

28. American Community Survey: Comparison Guidance • Comparing 2008, 2007 ACS and 2006 ACS • Census Bureau supports comparisons made between 2006 and 2007 ACS data • Comparing ACS to Census 2000 • Differences between the ACS and Census 2000 include residence rules, universes, and reference periods

29. American Community Survey: Design and Methodology Report • Important reference document covering methods used in producing ACS data • Available at: http://www.census.gov/acs/www/Downloads/tp67.pdf

30. American Community Survey: Similarities with Census 2000 • Same Questions and many of the same basic statistics • 5-year estimates will be produced for same broad set of geographic area including census tracts and block groups

31. American Community Survey: Key Differences from Census 2000 • Beginning in 2010, data for small geographic areas will be produced every year versus once every 10 years • Data for larger areas are available now and data for mid size area will be available in December 2008 • Census 2000 data describe the population and housing as of April 1, 2000 while the ACS data describe a period of thime and require data for 12 months, 36 months, or 60 months

32. American Community Survey: Key Differences from Census 2000 • The goal of ACS is to produce data comparable to the Census 2000 long form data • These estimates will cover the same small areas as Census 2000 but with smaller sample sizes • Smaller sample sizes for 5-year ACS estimates results in reductions in the reliability of estimates

33. For more Information: • ACS Website: • http://www.census.gov/acs/www/ • Data Analysis and User Education Branch: • 301.763.6355 • 301.349.8897