Occupational classification in the North Atlantic Population Project

The North Atlantic Population Project (NAPP) is a complete-count data set of late-nineteenth-century censuses from Canada, Great Britain, Iceland, Norway, and the United States. One of the project's most challenging tasks is the coding and classification of 2 million distinct responses to occupational questions. Using the Historical International Standard Classification of Occupations (HISCO) as the basis for their classification scheme, the authors have adapted it to address particular problems applicable to the NAPP occupational data—the inconsistent specification of tasks, industry, and employment status by census respondents; variation among the NAPP countries in the level of occupational detail provided; and spatial and temporal variation in the language used to describe occupations. Compared with HISCO's classification scheme, the NAPP system reduces the overall number of codes, introduces new codes, and retains more detail from vaguely specified occupations.