Realizing the Potential of the American Community Survey: Challenges, Tradeoffs, and Opportunities (2015)
Chapter: Appendix B: Examples of Differences Between Census Counts and ACS Population Estimates
Appendix B
Examples of Differences Between Census Counts and ACS Population Estimates
This appendix examines the magnitude of discrepancies between the 2010 census and 2008-2010 American Community Survey (ACS) counts for age-sex strata in a systematic selection of communities: Fort Wayne, Indiana; Sterling Heights, Michigan; San Clemente, California; Valparaiso, Indiana; Sunnyside, Washington; Rayne, Louisiana; and Ely, Nevada. Table B-1 shows the raw differences and Table B-2 shows the percentage differences. Many of the communities examined are the size of an average census tract. In many instances, the 2008-2012 ACS 5-year period estimates do not approximate the 2010 census results when 5-year age groups by sex are compared, and some comparisons include differences by factors as large as two.
For example, in Ely, Nevada (population 4,255), the ACS reported 201 females aged 30-34 while the census reported 103, a 95 percent difference. For males aged 15-19 years, the ACS reported 263 residents while the census reported 168, a 57 percent difference. For Rayne, Louisiana (population 7,953), the female population aged 35-39 years was reported in the ACS as 437 and in the census as 258; for all people aged 40-44, the ACS reported 153, and the census reported 257. Though not included in the table, similar differences appear in a sample of census tracts for the Bronx as well.
These problems are not confined to very small areas. For San Clemente, California (population 63,522), the number of females aged 85 and older in the ACS was 564, compared with 777 in the census, a 27 percent difference. For Fort Wayne, Indiana (population 253,691), the ACS reported
2,206 males aged 80-84, and the census reported 1,862, a 19 percent difference. The ACS also reported 1,253 males aged 85 and older, and the census reported 1,450, a 14 percent difference. That is, the differences are found for both tract and city estimates for geographic areas that are smaller than the county level. Even with the difference in reference periods (point-in-time census estimates and 2008-2012 ACS estimates), differences of this magnitude in 5-year age groups are larger than what one would reasonably expect.
TABLE B-1 Differences Between 2010 Census Counts and ACS 2008-2012 Population Estimates, by Sex and 5-Year Cohorts: Seven Cities
| Population, by Sex and Age Cohorts | Fort Wayne, Indiana | Sterling Heights, Michigan | San Clemente, California | Valparaiso, Indiana | Sunnyside, Washington | Rayne, Louisiana | Ely, Nevada | |||||||
| Census Total Population | 253,691 | 129,699 | 63,522 | 31,730 | 15,858 | 7,953 | 4,255 | |||||||
| Male | 666 | –812 | 1,036 | –147 | 86 | –25 | 96 | |||||||
Under 5 years | –33 | –355 | 1 | 95 | –177 | 212 | 3 | |||||||
5 to 9 years | 347 | –359 | –448 | 62 | 368 | –118 | 41 | |||||||
10 to 14 years | –169 | 174 | 368 | –96 | 94 | –43 | 55 | |||||||
15 to 19 years | –205 | 18 | 295 | 45 | –153 | –32 | –95 | |||||||
20 to 24 years | 95 | –18 | 252 | 187 | –147 | –71 | 42 | |||||||
25 to 29 years | 161 | –321 | 330 | 90 | 78 | 58 | 37 | |||||||
30 to 34 years | 98 | 182 | 258 | 105 | 248 | –26 | 43 | |||||||
35 to 39 years | 499 | 347 | –325 | –16 | –141 | –71 | –24 | |||||||
40 to 44 years | –193 | –455 | 114 | 81 | 34 | –410 | –9 | |||||||
45 to 49 years | 458 | –49 | 218 | 44 | 104 | 22 | 9 | |||||||
50 to 54 years | –82 | 114 | 155 | –174 | –43 | –32 | –12 | |||||||
55 to 59 years | 243 | –150 | 83 | –11 | –40 | –22 | 8 | |||||||
60 to 64 years | –460 | –16 | 34 | –27 | –93 | 57 | 6 | |||||||
65 to 69 years | 143 | 16 | –54 | 84 | –90 | 38 | 12 | |||||||
70 to 74 years | –41 | 65 | –155 | –165 | 33 | –16 | –5 | |||||||
75 to 79 years | –48 | 27 | –82 | 17 | 58 | 50 | 36 | |||||||
80 to 84 years | –344 | –144 | 25 | 12 | 22 | –10 | –33 | |||||||
85 years and older | 197 | 112 | –33 | 197 | –69 | 20 | –18 | |||||||
| Population, by Sex and Age Cohorts | Fort Wayne, Indiana | Sterling Heights, Michigan | San Clemente, California | Valparaiso, Indiana | Sunnyside, Washington | Rayne, Louisiana | Ely, Nevada | |||||||
| Female | –592 | 624 | –701 | 106 | –3 | 6 | –77 | |||||||
Under 5 years | –203 | 539 | –175 | –69 | 157 | 65 | 9 | |||||||
5 to 9 years | 245 | –252 | –171 | 21 | 73 | 88 | 34 | |||||||
10 to 14 years | –214 | 343 | –398 | –103 | 9 | 91 | –24 | |||||||
15 to 19 years | 305 | 86 | 436 | 321 | –11 | –47 | –83 | |||||||
20 to 24 years | 89 | –165 | –70 | –49 | –188 | –49 | 60 | |||||||
25 to 29 years | –318 | –142 | 288 | –169 | 185 | 41 | 39 | |||||||
30 to 34 years | –27 | –288 | –147 | 105 | 8 | 14 | –98 | |||||||
35 to 39 years | 93 | –54 | –415 | 46 | 123 | –179 | 35 | |||||||
40 to 44 years | 130 | 131 | –289 | 120 | –37 | 104 | –98 | |||||||
45 to 49 years | 65 | 203 | 510 | –150 | –198 | 9 | 26 | |||||||
50 to 54 years | –171 | 119 | –207 | 55 | 70 | –32 | –15 | |||||||
55 to 59 years | –2 | –95 | –159 | –10 | –24 | –7 | 7 | |||||||
60 to 64 years | –82 | 224 | –117 | –81 | –85 | 18 | 7 | |||||||
65 to 69 years | –59 | 76 | –89 | –11 | 1 | –16 | 16 | |||||||
70 to 74 years | –134 | –88 | –54 | –65 | –42 | –42 | 39 | |||||||
75 to 79 years | –56 | –73 | 155 | 44 | –74 | 2 | 20 | |||||||
80 to 84 years | –114 | –4 | –12 | 86 | –36 | 26 | –48 | |||||||
85 years and older | –139 | 64 | 213 | 0 | 66 | –80 | –3 | |||||||
| Summary of 5-Year Cohorts | |||||||||||||||
Maximum | 499 | 539 | 510 | 321 | 368 | 212 | 60 | ||||||||
Minimum | –460 | –455 | –448 | –174 | –198 | –179 | –98 | ||||||||
Percentage of county population | 71.4 | 15.4 | 2.1 | 19.3 | 6.5 | 12.9 | 42.4 | ||||||||
Sampling rate | 7.8 | 7.5 | 6.3 | 7.2 | 4.9 | 6.3 | 9.8 | ||||||||
Unweighted sample size of population | 19,764 | 9,748 | 3,981 | 2,276 | 775 | 499 | 415 | ||||||||
TABLE B-2 Percentage Differences Between 2010 Census Counts and ACS 2008-2012 Population Estimates, by Sex and 5-Year Cohorts: Seven Cities
| Population, by Sex and Age Cohorts | Fort Wayne, Indiana | Sterling Heights, Michigan | San Clemente, California | Valparaiso, Indiana | Sunnyside, Washington | Rayne, Louisiana | Ely, Nevada | |||||||
| Total Population | 0.0 | –0.1 | 0.5 | 1.2 | 0.5 | –0.2 | 4.4 | |||||||
| Male | 0.5 | –1.3 | 3.2 | 1.2 | 1.1 | –0.7 | 2.1 | |||||||
Under 5 years | –0.3 | –9.7 | 0.0 | –15.2 | –16.9 | 72.9 | 35.0 | |||||||
5 to 9 years | 3.7 | –9.2 | –19.5 | 9.5 | 42.2 | –35.8 | 43.0 | |||||||
10 to 14 years | –1.8 | 4.1 | 17.0 | 6.5 | 11.9 | –15.0 | –56.5 | |||||||
15 to 19 years | –2.2 | 0.4 | 13.6 | –7.5 | –20.1 | –10.7 | 34.4 | |||||||
20 to 24 years | 1.1 | –0.4 | 13.1 | 2.5 | –22.2 | –27.5 | 27.4 | |||||||
25 to 29 years | 1.8 | –8.0 | 16.7 | 13.6 | 13.1 | 25.7 | 38.7 | |||||||
30 to 34 years | 1.1 | 4.6 | 15.3 | 8.1 | 43.2 | –13.3 | –22.4 | |||||||
35 to 39 years | 6.2 | 8.3 | –15.3 | 10.3 | –29.6 | –37.0 | –7.7 | |||||||
40 to 44 years | –2.5 | –10.5 | 4.7 | –1.8 | 8.1 | –17.2 | 5.5 | |||||||
45 to 49 years | 5.5 | –1.0 | 8.5 | 8.7 | 25.9 | 7.9 | –6.9 | |||||||
50 to 54 years | –1.0 | 2.4 | 6.0 | 4.7 | –13.0 | –11.6 | 4.2 | |||||||
55 to 59 years | 3.2 | –3.5 | 3.9 | –19.9 | –14.7 | –9.9 | 4.2 | |||||||
60 to 64 years | –7.7 | –0.4 | 1.9 | –1.5 | –45.4 | 26.9 | 11.4 | |||||||
65 to 69 years | 3.6 | 0.5 | –4.2 | –6.2 | –55.2 | 25.9 | –5.8 | |||||||
70 to 74 years | –1.5 | 3.2 | –17.2 | 25.5 | 28.7 | –13.8 | 50.7 | |||||||
75 to 79 years | –2.1 | 1.9 | –12.1 | –54.6 | 61.7 | 50.5 | –70.2 | |||||||
80 to 84 years | –18.5 | –13.7 | 4.7 | 6.5 | 28.9 | –16.4 | –51.4 | |||||||
85 years and older | 13.6 | 12.5 | –7.0 | 4.7 | –78.4 | 44.4 | –3.7 | |||||||
| Female | –0.5 | 0.9 | –2.2 | 1.2 | 0.0 | 0.1 | 6.2 | ||||||||
Under 5 years | –2.1 | 15.5 | –9.1 | 11.6 | 16.4 | 23.1 | 27.6 | ||||||||
5 to 9 years | 2.7 | –6.9 | –8.0 | –7.7 | 9.0 | 31.4 | –18.2 | ||||||||
10 to 14 years | –2.4 | 8.8 | –18.8 | 2.3 | 1.2 | 33.3 | –64.3 | ||||||||
15 to 19 years | 3.3 | 2.1 | 22.0 | –8.6 | –1.6 | –17.2 | 47.6 | ||||||||
20 to 24 years | 0.9 | –4.1 | –4.4 | 16.9 | –31.2 | –21.0 | 35.1 | ||||||||
25 to 29 years | –3.4 | –3.4 | 16.6 | –4.0 | 29.3 | 14.8 | –95.1 | ||||||||
30 to 34 years | –0.3 | –7.2 | –8.3 | –16.7 | 1.4 | 6.5 | 37.2 | ||||||||
35 to 39 years | 1.1 | –1.3 | –18.5 | 10.7 | 25.9 | –69.4 | –77.8 | ||||||||
40 to 44 years | 1.7 | 2.9 | –11.5 | 5.1 | –8.4 | 40.5 | 16.9 | ||||||||
45 to 49 years | 0.8 | 4.0 | 19.6 | 12.6 | –52.4 | 3.0 | –8.5 | ||||||||
50 to 54 years | –1.9 | 2.3 | –8.5 | –14.2 | 20.8 | –10.7 | 4.5 | ||||||||
55 to 59 years | 0.0 | –2.0 | –7.4 | 5.8 | –8.7 | –2.7 | 5.4 | ||||||||
60 to 64 years | –1.2 | 5.3 | –6.4 | –1.2 | –38.6 | 7.3 | 15.1 | ||||||||
65 to 69 years | –1.2 | 2.3 | –7.1 | –14.9 | 0.5 | –7.9 | 44.3 | ||||||||
70 to 74 years | –3.7 | –3.7 | –5.3 | –2.1 | –24.3 | –25.1 | 29.0 | ||||||||
75 to 79 years | –1.7 | –3.9 | 19.4 | –15.1 | –64.3 | 1.5 | –92.3 | ||||||||
80 to 84 years | –3.8 | –0.2 | –1.7 | 9.0 | –28.3 | 23.4 | –4.2 | ||||||||
85 years and older | –4.1 | 3.0 | 27.4 | 14.0 | 36.9 | –78.4 | 0.0 | ||||||||
| Population, by Sex and Age Cohorts | Fort Wayne, Indiana | Sterling Heights, Michigan | San Clemente, California | Valparaiso, Indiana | Sunnyside, Washington | Rayne, Louisiana | Ely, Nevada | |||||||
| Summary of 5-Year Cohorts | ||||||||||||||
Maximum | 13.6 | 15.5 | 27.4 | 25.5 | 61.7 | 72.9 | 50.7 | |||||||
Minimum | –18.5 | –13.7 | –19.5 | –54.6 | –78.4 | –78.4 | –95.1 | |||||||
Mean absolute difference | 3.1 | 4.7 | 10.9 | 10.3 | 25.9 | 23.8 | 30.0 | |||||||
