American Community Survey (ACS) estimates with 0 values may have confidence intervals. The confidence intervals are possible because although households with the characteristics being measured may exist, these households may not be captured in the American Community Survey. Unlike the ACS, the U.S. Census captures all households; the 0 value represents the ACS findings, and margins of error are modeled using data from the Census.
For more information, please view the ACS webinar on margins of error.