Hot-Deck Imputation
Hot-Deck Imputation replaces missing data with comparable data from the same set. "Hot-deck imputation is a means of imputing data, using the data from other observations in the sample at hand." [1]
Hot-Deck Imputation may be used in the 2010 census. It is controversial for two reasons. First, the Constitution requires Actual Enumeration. Second, this type of imputation could easily be used to gerrymander districts in a fashion which will favor Obama's reelection.
This paper from the U.S. Bureau of the Census describes the Hot-Deck method in detail: http://analytics.ncsu.edu/sesug/1999/075.pdf
In surveying adults on probation, the Census Bureau follows a six-step process:
1. We impute age, race and gender independently.
2. For race, we first try to base imputation on other data (e.g., ethnicity) for the same person.
3. We impute all remaining missing values using only "good" unimputed) data for another person in the same group, or ctrlnum.
4. We use each "good" data value only once for imputation.
5. We work backwards over the ctrlnum; then, if necessary, we work forwards.
6. If no "good" data can be used from within the ctrlnum, we assign some type of "out of range" value.