For certain group quarters (GQ) characteristics and GQ types, the item non-response rates and coverage rates do not meet the Census Bureau's quality standards. The GQ coverage rate of 79.6 percent was below the standard of 80 percent. Most notably, the coverage rate for college dormitories was artificially low because data were collected throughout the entire year, including the summer months when many dormitories were vacant. This, in turn, lowers the coverage for the GQ population as a whole. Missing data for a particular question is called item nonresponse. It will occur when a respondent fails to provide an answer to a question or when an invalid answer is provided. The Census Bureau uses allocation methods to correct for item nonresponse and thus, allocation rates are used to measure the magnitude of item nonresponse. The Census Bureau has established a standard states that users should be made aware of items with allocation rates exceeding 20 percent. Several GQ population characteristics in the subject tables did not meet this standard. For example, item allocation rates for characteristics such as year of entry and income were high for certain GQ types and for the GQ population as a whole. A separate document provides item allocation rates for GQ characteristics that did not meet the Census Bureau's quality standard. High item allocation rates and low coverage rates can adversely impact final estimates for the GQ population and introduce bias if the characteristics of nonrespondents differ from those of respondents. If the GQ population makes up a large proportion of the total population for an area, the estimates for the total population can likewise be affected.