Why are some data not displayed in the demographic tables?
According to the U.S. Census Bureau, even if a geography meets the population threshold of 65,000, some very detailed tables might include estimates whose reliability are unacceptable. Since 2005, data release rules based on the statistical reliability of the estimates have been used to determine whether a table is published for a geography. The main data release rule for the ACS tables works as follows. Every detailed table consists of a series of data cells that contain estimates. If more than half of those estimates are not statistically different from 0, then the table fails. Each estimate is subject to sampling variability that can be summarized by its standard error. Dividing the standard error by the estimate yields the coefficient of variation (CV) for each of the estimates. (If the estimate is 0, a CV of 100 is assigned.) To implement the data release requirement, CVs are calculated for each of the table’s estimates and the median CV value is determined. If the median CV value
