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Notes on ACS 1-Year Data

Component ID: #ti1306587646

Please note that ACS 1-Year Data may return the following in place of data:

  • A '**' entry in the margin of error column indicates that either no sample observations or too few sample observations were available to compute a standard error and thus the margin of error. A statistical test is not appropriate.
  • A '-' entry in the estimate column indicates that either no sample observations or too few sample observations were available to compute an estimate, or a ratio of medians cannot be calculated because one or both of the median estimates falls in the lowest interval or upper interval of an open-ended distribution.
  • A '-' following a median estimate means the median falls in the lowest interval of an open-ended distribution.
  • A '+' following a median estimate means the median falls in the upper interval of an open-ended distribution.
  • A '***' entry in the margin of error column indicates that the median falls in the lowest interval or upper interval of an open-ended distribution. A statistical test is not appropriate.
  • A '*****' entry in the margin of error column indicates that the estimate is controlled. A statistical test for sampling variability is not appropriate.
  • An 'N' entry in the estimate and margin of error columns indicates that data for this geographic area cannot be displayed because the number of sample cases is too small.
  • An '(X)' means that the estimate is not applicable or not available.
  • An * indicates that the estimate is significantly different (at a 90% confidence level) than the estimate from the most current year. A "c" indicates the estimates for that year and the current year are both controlled; a statistical test is not appropriate.

Component ID: #ti1500274381

Notes on Annotation Values and Variable Endings

ACS 1-Year Data contain variables ending in E, EA, M, MA, PE, PM and SS. See the table below for each variable type and its meaning:

Variable Type Title Related Products Meaning
E Estimate Summary Files, Subject Tables, Data Profiles, Comparison Profiles A numeric representation of the estimate.
EA Estimate Annotation Subject Tables, Comparison Profiles A character representation of the estimate. If an Estimate Annotation exists, use this value in place of the Estimate. (See Example #1 below)
M Margin of Error Summary Files, Subject Tables, Data Profiles A numeric representation of the margin of error.
MA Margin of Error Annotation Subject Tables Only A character representation of the margin of error. If a Margin of Error Annotation exists, use this value in place of the Margin of Error.
PE Percent Estimate Data Profiles Only An estimate representing a percent of the total.
PM Percent Margin of Error Data Profiles Only The Margin of Error for the corresponding Percent Estimate (PE) variable
SS Statistical Significance Comparison Profiles Only Returns ‘*’ or ‘c’ representing the Statistical Significance for the corresponding estimate (E) variable. (See Example #2 below)

An * indicates that the estimate is significantly different (at a 90% confidence level) than the estimate from the most current year. A "c" indicates the estimates for that year and the current year are both controlled; a statistical test is not appropriate.

Example #1: Estimate Annotations

Figure 1: Visual Representation of S0101_C02_031E/A from American Factfinder

Component ID: #ti1500274380

In the following example, the variable S0101_C02_031EA returns “(X)”. Using the notes above, this indicates that the estimate is not applicable or not available. Since S0101_C02_031E represents the Sex Ratio (males per 100 females) and the column is for Males only this estimate is not applicable. S0101_C02_031E returns -888888888 as a caution not to use this estimate in reporting or further calculations. See Figure 1 above for a visual context for this estimate.

api.census.gov/data/2015/acs1/subject?get=NAME,S0101_C02_031E,S0101_C02_031EA,S0101_C02_031M,S0101_C02_031MA&for=us:*

Returns:

[["NAME","S0101_C02_031E","S0101_C02_031EA","S0101_C02_031M","S0101_C02_031MA","us"],

["United States","-888888888","(X)","-888888888","(X)","1"]]

Example #2: Statistical Significance

Figure 2: Visual Representation of CP02_2015to2014_001SS from American Factfinder

Component ID: #ti1500274379

In the following example, the variable CP02_2015to2014_001SS returns “*”. Using the notes above, this indicates that the 2015 estimate for Total households is significantly different when compared to the 2014 estimate.

api.census.gov/data/2015/acs1/cprofile?get=NAME,CP02_2015_001E,CP02_2014_001E,CP02_2015to2014_001SS&for=us:*

Returns:

[["NAME","CP02_2015_001E","CP02_2014_001E","CP02_2015to2014_001SS","us"],

["United States","118208250","117259427","*","1"]]

Component ID: #ti1500274378

More on Annotation Values

See the table below for a list of common Estimate/Margin of Error (E/M) values and their corresponding Annotation (EA/MA) values. See section above titled “Notes on ACS 1 Year Data” for Annotation Values and its meanings.

Estimate Value Annotation Value
-999999999 N
-888888888 (X)
-777777777 (Z)
-666666666 -
-555555555 *****
-333333333 ***
-222222222 **

X
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