Home > Data Services > Catalog . Restricted Data . Census . ACS

Search Data Services

Meta Search
search across all the following databases:

Data Catalog
Data and documentation

KnowledgeBase
Common questions and answers.

Resources
Entire collection of data resources.


Latest Data News

RSS Feed icon

Tools: Data as Text

More fun with names

Counting Same-Sex Couples

The Antidote for “Anecdata”: A Little Science Can Separate Data Privacy Facts from Folklore

Big Data: NYC Taxi Cab Trips

Why are there zero weights in the 1990 Census?

The Census Bureau used integer values for weights to avoid complications in rounding for tabulated data. If the final weight of the persons in a particular group was .80, then 4/5 of them were randomly assigned to get a weight of 1 and 1/5 of them were randomly assigned to get a weight of 0. This logic applies to other weights. A weight of 5.5 for a group of persons means half of the persons in this group were randomly assigned a weight of 5 and half of the persons in this group were assigned a weight of 6.

For further discussion of this, see page 4-3 in the technical documentation to the 1990 PUMS.

Source: Census of Population and Housing, 1990: Public Use Microdata Sample U.S. Technical Documentation / prepared by the Bureau of the Census. Washington: The Bureau, 1992.