Building Permits	Geographic Coverage Source of Information and Limitations
Beginning with Annual 1995 and January 1996 this file provides building permit statistics on new privately-owned residential construction. For the years 1980-1994 and the months from January 1988 through December 1995, this file provides building permit statistics on new residential and nonresidential construction; additions, alterations and conversions; and demolitions. These are provided for individual permit-issuing jurisdictions. Geographic Coverage Most of the permit-issuing jurisdictions are municipalities; the remainder are counties, townships, or unincorporated towns. For the municipalities, and townships or towns, the area subject to building permit requirements to which the figures pertain is normally that of the governmental jurisdictions. A small number of municipalities have authority to issue building or zoning permits for areas extending beyond their corporate limits. In such cases, the data relate to the entire area within which the permit-issuing authority is exercised. Similarly, a small number of townships issue permits for only a part of the township and the data normally covers only the area subject to the township's permit system. Source of Information and Limitations Statistics provided in these files are based upon reports submitted by local building permit officials in response to a mail survey. If an official fails to respond and the permit-issuing place is in our Residential Permit Use Survey (SUP), then the residential housing unit data are obtained from that survey and nonresidential, nonhousekeeping and demolition data are imputed. The SUP (a component of the Survey of Construction) is a survey in which interviewers go to approximately 850 selected permit offices and list data from each building permit that authorizes construction of new residential housekeeping buildings. If no report is received and the place is not in SUP, then all data items are imputed. Limitations of Data The portion of construction measurable from building permit records is inherently limited since such records obviously do not reflect construction activity outside of the area subject to local permit requirements. For the nation as a whole, less than 5 percent of all privately owned housing units built are construction in areas that do not require building permits. The reported statistics are also influenced by the following factors: Some building permit jurisdictions close their books a few days before the end of the month/year, so that the time reference for permits is not, in all cases, strictly the calendar month/year. A study spanning 4 years showed that about 3 percent of the single-family houses built in permit-issuing places are built without a permit. To the extent that most of these limiting factors apply rather consistently over an extended period, they may not seriously impair the usefulness of building permit statistics as prompt indicators of trends in residential construction activity. Questions should be directed to Manufacturing and Construction Division, Bureau of the Census, Washington, D.C. 20233-6900. Phone: (301) 457-1321.