What are topcoding and bottomcoding? How can I tell if a value has been topcoded or bottomcoded in the American Housing Survey (AHS) public use file (PUF)? What rules does the AHS use for this?

To ensure respondent confidentiality, the Census Bureau requires that disclosure avoidance techniques be applied to certain PUF variables. Topcoding and bottomcoding are disclosure limitation techniques that involve limiting the maximum or minimum value of a variable allowed on the file to prevent disclosure of units with extreme values in a distribution (e.g., outliers). More information about disclosure methodology for all AHS variables, including the impact of noise injection, can be found in the Disclosure Avoidance Techniques: 2015 to 2023 documentation.