The Copenhagen Tax Books

2.1 million taxpayer records, 1862–1919

Historical inequality is usually measured badly, because the sources are thin. Researchers work from tax tabulations already aggregated by the authorities, from top-income shares reconstructed out of fragments, or from occupational proxies standing in for income that was never recorded. Copenhagen is an exception: the city assessed and recorded its taxpayers individually, year after year, and the books survive.

This project transcribes them - 2.1 million records covering nearly sixty years, from 1862 to 1919 - and reconstructs the distribution of income and wealth in the Danish capital across the period in which it industrialised, roughly quadrupled in population, and built the institutions of a modern city.

What individual records change

Aggregate tabulations tell you the shape of a distribution in a given year. Individual records linked over time tell you something categorically different: who moved within it. Whether the same families stayed at the top; whether industrialisation raised incomes broadly or concentrated them; how occupational structure and income actually corresponded, rather than as assumed by a coding scheme; and how mobility in a rapidly growing city compared with the countryside people were arriving from.

Because the records are annual and name individuals, they can be linked both to each other over time and to the censuses and parish registers — which is where this project connects to the rest of the unit's work, and where OccCANINE does the occupational coding.

Method

The tax books are printed and handwritten by turns, with layouts that change as the city's administration reorganised. They are a good test of the unit's table-recognition and structuring methods at genuine volume: 2.1 million records is far past the point where any error-checking strategy based on human review of every entry remains possible, so the accuracy has to come from the method and be demonstrated by sampling.