Compare methods

	HISCO Occupational Coding	Occupational Structure Reconstruction
Field	Social History	Economic History
Family	Process / pipeline	Process / pipeline
Year of origin	2002	2010
Originator	Marco H. D. van Leeuwen, Ineke Maas, and Andrew Miles	E. A. Wrigley and the Cambridge Group for the History of Population and Social Structure
Type	measurement-classification	descriptive-reconstruction
Seminal source	van Leeuwen, M. H. D., Maas, I., & Miles, A. (2002). HISCO: Historical International Standard Classification of Occupations. Leuven University Press. ISBN: 9789058671967	Wrigley, E. A. (2010). The PST System of Classifying Occupations. Cambridge Group for the History of Population and Social Structure.
Aliases	HISCO coding, Historical occupational classification, Standardized occupational titling, Occupational title harmonization	PST occupational coding, Sectoral structure reconstruction, Primary-secondary-tertiary classification, Cambridge occupational structure
Related	3	3
Summary	HISCO, the Historical International Standard Classification of Occupations, is a coding scheme that translates the messy free-text occupational descriptions found in historical records into a single standardized, hierarchical classification. Built by van Leeuwen, Maas, and Miles on the framework of the modern ILO ISCO-68, it lets a 'cordwainer' in eighteenth-century England, a 'cordonnier' in France, and a 'Schuhmacher' in Germany all resolve to the same shoemaker code. Occupational titles are the single richest indicator of social and economic position in pre-modern records, appearing in censuses, marriage registers, tax lists, and directories. But their idiosyncratic spelling, multilingual diversity, and archaic vocabulary make raw comparison impossible. HISCO provides the controlled vocabulary and coding rules that turn these strings into analysable data, forming the indispensable first layer beneath class schemes, mobility studies, and occupational structure reconstruction.	Occupational structure reconstruction uses the distribution of the workforce across economic activities to chart how an economy's sectoral composition evolved before modern statistics. The Cambridge Group, led by E. A. Wrigley, developed the Primary-Secondary-Tertiary (PST) system, a classification purpose-built for historical occupational descriptors that sorts every recorded occupation into agriculture and extraction (primary), manufacturing and processing (secondary), or trade, transport, and services (tertiary), with finer subdivisions beneath. By coding occupations from censuses, parish registers, probate inventories, trade directories, and militia lists, the method estimates the share of workers in each sector and tracks its movement across benchmark years. Because the shift from primary to secondary and tertiary employment is the structural signature of economic development, these reconstructions illuminate the timing and geography of industrialization with a directness that aggregate output figures cannot match, complementing and constraining national-accounting estimates of growth.