Data from death records of 1,906 Catholic parishes and other entities in 11 Texas dioceses during January to June 1980 were used to estimate sensitivity of Hispanic population data to various identifications of "Hispanic." Self-identification as Hispanic, as on the 1980 census, appeared unreliable; the Census Bureau was expected to recode 1980 census records according to an expanded list of Spanish surnames. The new Texas death certificate asked for father's surname and "Was the decedent of Spanish origin?", but less was known about third-party identification in vital statistics than about self-identification. To check whether Census Bureau and Texas data for estimating Hispanic population accurately identified persons whom local sources classified as Hispanic, questionnaires, accompanied by letters from local bishops encouraging cooperation, were mailed to Texas Catholic pastors, who knew the decedents' backgrounds, asking them to identify Hispanic decedents. Response rate was 100%; 8,163 deaths were tabulated and compared statistically to data from the Texas Bureau of Statistics GUESS computer program, which used linguistic principles to determine origin of surname, and the Census Bureau's improved list of Spanish surnames. Census Bureau and Texas classification programs yielded remarkably similar results; local third-party definition yielded a larger number of Hispanics, especially Hispanic women. (MH)