ACS 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 in Estimate and Annotation Values) | 
| 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  in Estimate and Annotation Values) 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. |