Navigating the Census Bureau’s American Community Survey Data:

1. Navigating the Census Bureau’s American Community Survey Data: Accessing Multiyear Data for Hawaii Morgan Walls-Dines, Ph.D. Information Services Specialist Los Angeles Regional Office U.S. Census Bureau 1/09

2. Overview of Session • Background of Decennial and ACS • Overview of ACS • ACS Multiyear Data • Questions & Break • Part II: How to access ACS Data using the Website

3. Decennial Census In Census 2000, the census used 2 forms “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 by the resident “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 Only a small portion of the population, called asample, received the long form. 3 3

4. 2010 Census and ACS 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 4

5. What is the American Community Survey? 5 5

6. ACS Overview • The ACS is a large, continuous demographic survey • The ACS produces annual and multi-year estimates of the characteristics of the population and housing • Produces characteristics, not a population count • Key component of the decennial census program

7. Target Population Resident population of the United States and Puerto Rico - Living in housing units and group quarters Current residents at the selected address - “Two month” rule 7 7

8. Sample • Questionnaires mailed to about 1 in 480 addresses each month throughout the U.S. and Puerto Rico. • 1 in 40 addresses per year (2.5% of the population). • Average of 500-600 addresses per month per congressional district. • Total of 3 million addresses each year, or 250,000 per month. • Inclusion of population in group quarters beginning in 2006.

9. American Community Survey: Content 9 9

10. Social Characteristics Education Marital Status Fertility Grandparent Caregivers Veterans Disability Status • Place of Birth • Citizenship • Year of Entry • Language Spoken at Home • Ancestry/Tribal Affiliation 10 10

11. Economic Characteristics Income Benefits Employment Status Occupation Industry Commuting to Work Place of Work 11 11

12. Housing Characteristics Tenure (own vs. rent) Occupancy & Structure Housing Value Taxes & Insurance Utilities Mortgage/Monthly Rent 12 12

13. Demographic Characteristics Sex Age Race Hispanic Origin 13 13

14. 2008 Content Changes Three new questions Health Insurance Coverage Veteran’s Service-connected Disability Marital History Deletion of one question Time and main reason for staying at the address Changes in some wording and format 14 14

15. Methodology Sample includes about 3 million addresses each year Three modes of data collection mail phone personal visit Data are collected continuously throughout the year 15 15

16. 2007 American Community Survey Data for Geographic Areas with 65,000 or more Population State -Hawaii Counties –Hawaii Co., Honolulu Co., Maui Co. County Subdivisions Places –Honolulu CDP Metropolitan Areas –Honolulu Metro Area Congressional Districts – 110th -CD1, CD2 American Indian Areas School Districts –HI Dept. of Education Public Use Microdata Areas –00100, 00200, 00301 through 00307

17. Reference Map of Honolulu CDP

18. Using the Data:Factors to Consider • Universe and residence rules • Time Periods • Reference Periods

19. ACS Universe • Total resident population of the United State and Puerto Rico • Household population in 2005 and prior ACS years • Group Quarters population added to sample in 2006

20. Residence Rules • The American Community Survey uses a “two-month” rule • Decennial census based upon the concept of “usual residence”

21. Residence Rules • Resident of a housing unit if a person: - Lives there year round - Lives there more than 2 months but not year round - Is living there now with no other place to live - Is away now for 2 months or less • Not a resident of a housing unit if a person: - Lives there 2 months or less with another residence - Is away now for more than 2 months

22. Period Estimates • Describes the characteristics of an area over a specific period of time • Contrasts with point-in-time estimates that describe the characteristics of an area on a specific date • 1-year, 3-year, and 5-year estimates are released for geographic areas that meet specific population thresholds

23. Reference Periods • ACS uses the interview date as the single reference point, or as the end of a reference period, for all data collection.

24. Questions With No Specific Reference Period • 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

25. Questions With a Specific Reference Period Relative to Interview Date • 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

26. Group Quarters • Place where people live or stay that is normally owned or managed by an entity or organization providing housing or services for the residents. Two types of group quarters: 1. Institutional 2. Non-institutional Group Quarters Population includes all people not living in households. - This term includes those people residing in group quarters as of the date the ACS was conducted.

27. Overview of ACS Timeline • First year of data collection for full sample in 2005. • Data for calendar year 2007 released beginning in August 2008. • Annual data for geographic areas over 65,000 population. • 3 year averages are now available for geographic areas 20,000 to 65,000. • 5 year averages for geographic areas under 20,000 in 2010.

28. Timeline • ACS Data single year collection (e.g. 2007) is closed out just after the beginning of a calendar year (e.g. 2008) • Single-year and multiyear data products start to become available in the summer of the same year. • For example 2007 ACS estimates were released in 2008 • The cycle repeats EVERY year

29. Release Schedule for ACS Data

30. Data Products Release Schedule * Five-year estimates will be available for areas as small as census tracts and block groups. Source: US Census Bureau 30 30

31. What do I need to know before using ACS data and data products?

32. Understanding Estimates and Margin of Error

33. Estimates • ACS data are estimates • ACS data are not counts of the population or housing • Population counts are produced from the decennial census - Counts are updated throughout the decade through the Population Estimates Program

34. Margin of Error (MOE) • Definition: • A measure of the precision of an estimate at a given level of confidence (90%, 95%, 99%) • MOEs at the 90% confidence level for all published ACS estimates • Confidence Interval • Definition: • A range that is expected to contain the population value of the characteristic with a known probability.

35. Family Income in Past 12 Months (In 2007 Inflation-Adjusted Dollars)

36. Interpreting Margin of Error • Indicates 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

37. American Community Survey: Multiyear Data 2007 2005 2006

38. Review: Period Estimate Definition: An estimate that describes the average characteristics of an area over a specific time period. - Period for ACS 1-year estimates is the calendar year - Different from a point-in-time estimate

39. What is a Multiyear Estimate? Definition: A period estimate that encompasses more than one calendar year. Period for ACS multiyear estimates is either 3 or 5 calendar years

40. Population Thresholds for ACS Estimates

41. Constructing Multiyear Estimates • Data are pooled across 36 or 60 months • Data are weighted to produce estimates • Estimates are controlled for age, sex, race, and Hispanic origin • Multiyear estimates are not an average of 1-year estimates

42. When should I use multiyear estimates?

43. Use Multiyear Estimates When … • No 1-year estimate is available • Margins of error for 1-year estimates are larger than required • Analyzing data for small population groups

44. Currency vs. Reliability

45. Reliability Note: Fictional data

46. What should I be aware of when using multiyear estimates?

47. Inflation Adjustment • Dollar-valued data items are inflation adjusted to the most recent year for the period • Income, rent, home value, and energy costs • Adjusted using inflation factors based on the Consumer Price Index (CPI) • Adjustment designed to put the data into dollars with equal purchasing power

48. Geographic Boundaries • Multiyear estimates are based on geographic boundaries as of January 1 of the last year in the multiyear period • Boundary Annexation Survey collects boundary changes • Boundaries of other statistical areas will be updated every decade in conjunction with the decennial census

49. Geographic Boundaries Amarillo city, Texas

50. Population Controls • Estimates of housing units and people are controlled to the population estimates derived from the Population Estimates Program • Multiyear estimates are controlled to the average of the individual year’s estimates for the period