1. Acquiring socio-economic and business data for neighborhood analysis Open a web browser and go to: http://tinyurl.com/tufts-census Barbara Parmenter Tufts Geospatial Services

2. US Census Bureau Collection Methods Three basic methods of collection Census (100%) Survey (sample) Administrative records

3. Two Types of Census by the US Decennial census: population and housing  On the 0’s (2000, 2010) Economic census: business and industry  On the 2’s and 7’s (2002, 2007, 2012) Census = the enumeration of entire population or universe of collection units such as housing units or businesses

4. Survey Types Data collected from sample of population, that represents the full population American Community Survey - monthly Current Population Survey - monthly Survey of Income and Program Participation - monthly American Housing Survey - every 2 years

5. Most important for Neighborhood scale analysis: Decennial Census Once every 10 years 100% count* Very small sampling error Basic information on population, race/Hispanic ethnicity, age, family structure, housing units, owner/renter housing tenure American Community Survey Released yearly with rolling multi-year averages Sample survey High sampling error for small areas (e.g., neighborhood level) Detailed information on income, education, commute, place of birth, etc.

6. Census Geography

7. Census Blocks

8. Census Block Groups

9. Census Tracts

10. We will focus on: The American Community Survey (ACS) How to map census / ACS data in Social Explorer Understanding sampling error for the ACS Using Reference USA to get business data for a neighborhood

11. Let’s take a look at the 2010 Census form…

12. American Community Survey Continuous monthly survey Began in 2005 It has replaced the decennial census long form

13. Look at the American Community Survey Questionnaire

14. Think about how people would respond to these questions Accuracy of answers? Would you know when your house was built? Do you know how much you spent for heating costs? Concerns about privacy?

15. Open Social Explorer

20. Basic types of information from the Census 100% SF1 data

21. Explore the basic types of information from the Census 2010 100% data

22. More Census 2010…. This is all data from the 100% Census

23. Explore mapping population 85 and older

24. Explore mapping population 85 and older…

27. Population 85+ by state…

28. Change preferred geography to census tracts

29. Population 85+ by census tract…

30. Zoom in to a smaller area either using the zoom in tool (+) or typing in a place name

31. Boston 85 and over by census tract…

32. Now let’s look at ACS data…

33. ACS 2008-2012 (5 year estimates) Explore the different data you can find here

34. Try mapping median house- hold income by census tract

36. Saving your maps…

38. Saving your maps…options

39. Saving your maps…Download

40. Save it where you can find it again!

41. Understanding the ACS “5 year estimates”

42. IMPORTANT: ACS Release Schedule – data is released as averages: 1 Year – areas with a population 65,000+ 3 Years – areas with a population 20,000+ 5 Years - all other areas (including census tracts and blockgroups) E.g., average median household income for 2008-2012 (released December, 2013)

43. Huh????

44. Let’s see an ACS 1-year estimate…

45. Zoom out and map by County…

46. Lots of counties have less than 65,000 people!

47. IMPORTANT: ACS Release Schedule – data is released as averages: 1 Year – areas with a population 65,000+ 3 Years – areas with a population 20,000+ 5 Years - all other areas (including census tracts and blockgroups) E.g., average median household income for 2008-2012 (released December, 2013)

48. Try mapping the most recent ACS 3-year estimates Median household income by county

49. More counties are mapped…the ones with at least 20,000 people

50. IMPORTANT: ACS Release Schedule – data is released as averages: 1 Year – areas with a population 65,000+ 3 Years – areas with a population 20,000+ 5 Years - all other areas (including census tracts and blockgroups) E.g., average median household income for 2008-2012 (released December, 2013)

51. Now map median household by county using the ACS 5- year 2008-2012 estimates…

52. And while you’re at it, map 5 classes by quantiles…

53. ACS 5-year estimates – median household income by county

54. ACS 5-year estimates – all counties have data

55. IMPORTANT: ACS Release Schedule – data is released as averages: 1 Year – areas with a population 65,000+ 3 Years – areas with a population 20,000+ 5 Years - all other areas (including census tracts and blockgroups) E.g., average median household income for 2008-2012 (released December, 2013)

56. To map by tract you HAVE to use the ACS 5-year estimates!!

57. If you don’t believe me, you can try…

58. So get to using the 5 year estimates

59. Unique Geographic Identifiers Federal Information Processing Standards (FIPS) Codes AreaName2000 FIPS StateMassachusetts 25 CountySuffolk25025 Tract611.0125025061101 Blockgroup02250250611012 Block01250250611012001

60. Block 250250611012001

61. Some other important definitions to understand

62. Housing Unit A house, an apartment, a mobile home or trailer, a group of rooms, or a single room occupied as separate living quarters, or if vacant, intended for occupancy as separate living quarters. Separate living quarters are those in which the occupants live separately from any other individuals in the building and which have direct access from outside the building or through a common hall. For vacant units, the criteria of separateness and direct access are applied to the intended occupants whenever possible.

63. Household Household: all persons who occupy a housing unit Important: housing unit and household are TWO different things! Don’t get them confused!

64. Two Types of Households Family Household: householder plus all persons in the household related by blood, marriage, or adoption Can also include:  Subfamily Example: householder’s son and daughter-in-law  Nonrelative Example: roomers, boarders Nonfamily Household: persons living alone or with nonrelatives only

65. Example: income options Median household income Median family household income Median non-family household income Per capita income Etc… Which would be most important for your research?

66. The “universe” for each variable The total number of units, e.g., individuals, households, businesses, in the population of interest. This is important for understanding percentages Know your “universe”! Make sure you understand what is the universe.

67. Barnstable County, MA

69. Making reports in Social Explorer Go back to Social Explorer Zoom in to Boston or another area, or zoom into an address to find your census tract of interest

70. Let’s make a report about a neighborhood…

72. Use the point option and point to your census tract of interest, and the adjoining tracts…

73. When ready, click Show Report

74. Note the report has the details for every tract we selected…

75. Use the Excel tab to download a report

76. Our neighborhood report…

77. Our neighborhood report…tract of interest

78. Our neighborhood report…totals for all tracts in our selection

79. Warning: there is a BIG problem for neighborhood level analysis…

80. The decennial census data at the census block, block group and tract level is very reliable – why?

81. But the ACS is very problematic for those small areas. Why?

82. ACS and Margin of Error Means of transportation for commute – Tract Level - ACS 2005-2009 5 year estimates Universe is workers 16 and over Workers 16 and Over

83. So let’s understand the margin of error…

84. What is Sampling Error? Definition The uncertainty associated with an estimate that is based on data gathered from a sample of the population rather than the full population 84

85. Illustration of Sampling Error Estimate average number of children per household for a population with 3 households living in a block: Household A has1 child Household B has2 children Household C has3 children The block average based on the full population is two children per household: (1+2+3)/3 85

86. Conceptualizing Sampling Error Three different samples of 2 households: 1. Households A and B (1 child, 2 children) 2. Households B and C (2 children, 3 children) 3. Households A and C (1 child, 3 children) Three different averages based on which sample is used: 1. (1 + 2) / 2 = 1.5 children 2. (2 + 3) / 2 = 2.5 children 3. (1 + 3) / 2 = 2 children 86

87. Sampling Error Census 2010 is a 100% survey so has smaller error ACS data is based on samples – error is larger The smaller the geography, the larger the error (because the sample is smaller) Especially true for variables that sample a small number of people, e.g., bike commuters

88. ACS and Margin of Error Means of transportation for commute – Tract Level - ACS 2005-2009 5 year estimates Universe is workers 16 and over Workers 16 and Over

89. Bottom line for ACS More up to date information Continuous versus point in time measurement 5 year estimates are the most reliable because they have the largest samples But…  Poorer precision at finer scales (e.g., census tract) or areas of low population (rural areas)  Poorer precision for variables with low numbers (e.g., people who bike to work)

90. How can I see the margin of error?

91. Return to Social Explorer Home and click on Maps and Tables…

92. Choose the ACS (5 year Estimates)

93. Choose 2008-1012 and click on Begin Report

103. Open Excel file, enable editing and/or save a copy…

104. Add columns for CV, MOE, Lower, and Higher

105. Measures Associated with Sampling Error Standard Error (SE) Coefficient of Variation (CV) Margin of Error (MOE) 105

106. Standard Error (SE or Std. Error) Definition A measure of the variability of an estimate due to sampling Depends on variability in the population and sample size The Census Bureau calculates the Standard Error for its estimates. 106

107. Coefficient of Variation (CV) Definition The relative amount of sampling error associated with a sample estimate (by estimate, we mean the value, like number of people biking to work) The CV helps to interpret reliability Formula CV = Standard Error / Estimate * 100 107

108. Calculating the CV… CV = (Std. Error / Estimate) * 100

109. CV% is a measure of reliability. So what is a good CV %? No agreement Depends on purpose Census case studies:  less than 15% may be reliable  15-30% - not reliable, be very careful  Over 30% - not reliable, use with extreme caution

110. Our CV’s calculated for Census Tract public assistance…

111. Margin of Error (MOE) at 90% confidence level Definition If we sampled the population many times, we could be confident that 90% of the time, the true value for the population would fall between our upper and lower margin of error Census Formula for MOE Margin of Error = SE * 1.645 (for 90% confidence level) 111

112. Calculating the MOE at 90% confidence level… MOE = SE * 1.645 (using Census constant)

113. Calculating the lower limit of the MOE at 90% confidence level… Lower limit = the estimate minus the MOE

114. Calculating the upper limit of the MOE at 90% confidence level… Upper limit = the estimate plus the MOE

115. What have you learned?

116. Take home points There are two major Census Bureau products used for neighborhood analysis:  The Decennial Census Basic data By block, block group, and tract Once a decade, one point in time  The American Community Survey Lots of interesting data By tract – but high sampling error! More up to date – 5-year rolling estimates

117. Policy Map is another mapping tool…

118. Census AND lots of other data from various agencies and organizations…

120. Also accessed through Tisch Library’s databases…

121. Take home points Social Explorer is a useful mapping, presentation, and reporting tool for current and historical census data Policy Map is another interesting tool for current and recent census data, as well as other policy-related data

122. Acquiring business data for your neighborhood using Reference USA Also through Tisch Library - Databases

124. Scroll down the results list and you’ll find it…

126. We are going to acquire business data using: Geography - options include  Radius from an address  Zip code Type of business  Using industry groupings, e.g., retail – food – grocery stores

136. Download Excel file to desktop…

137. Open Excel file and look through it

138. Use SAVE AS to save to a name and place where you can find it again…

139. Note: there is a 50 record download limit for our license of Reference USA (per Excel file)

140. Mapping your business data in Google Maps Requires a google account If you don’t have one, sit with someone who does…

141. Open a web browser and go to maps.google.com, then click on settings tool

142. Click on My Places and sign in with your google account

144. Create Map…

146. Choose IMPORT…

148. First choose the address information…

149. Next choose something for the map label…

150. My map…

151. My map…with store info

152. Give it a name and description and save it…

153. Share it as you like…

154. Whew!!! What you have learned… Social Explorer for Census and American Community Survey (ACS) data (historical and current, maps and tables) About sampling error in the ACS Policy Map for some other types of data Reference USA for business and services data Google Maps for mapping Reference USA data

155. Questions? Barbara.Parmenter@tufts.edu Tufts Geospatial Services