Yes. The housing adequacy measure is a composite based on responses to many instrument questions related to housing quality. While the basic algorithm behind the measure has remained stable, some changes have occurred, either because of changes in data collected by the survey or because of changes in the way survey questions were phrased. Users may want to compare the descriptions of ZADEQ/ADEQUACY in the PUF Codebook. Another useful resource is the HUD-commissioned report, "American Housing Survey: Housing Adequacy and Quality As Measured by the AHS".