In 2015, the American Housing Survey (AHS) introduced a new variable to its questionnaire: GUTREHB. GUTREHB identifies owner-occupied units that had undergone transformation within the previous 10 years, and was intended by its authors to provide information about how the housing stock evolves over time. This publication provides background information on the GUTREHB variable, using data from the 2015, 2017, and 2019 AHS survey to assess its utility and reliability. The author concludes with an exploration of possible future directions for the variable.