Compare methods

	Counterfactual Historical Reasoning	Occupational Structure Reconstruction
Field	History	Economic History
Family	Process / pipeline	Process / pipeline
Year of origin	1964	2010
Originator	Robert Fogel (rigorous cliometric form); Max Weber and Geoffrey Hawthorn (philosophical foundations)	E. A. Wrigley and the Cambridge Group for the History of Population and Social Structure
Type	conceptual-analytic	descriptive-reconstruction
Seminal source	Fogel, R. W. (1964). Railroads and American Economic Growth: Essays in Econometric History. Johns Hopkins Press. ISBN: 9780801805547	Wrigley, E. A. (2010). The PST System of Classifying Occupations. Cambridge Group for the History of Population and Social Structure.
Aliases	What-if history, Counterfactual analysis, Minimal-rewrite counterfactuals, Plausible-world reasoning	PST occupational coding, Sectoral structure reconstruction, Primary-secondary-tertiary classification, Cambridge occupational structure
Related	3	3
Summary	Counterfactual historical reasoning is the disciplined practice of asking what would have happened had some past condition been different, in order to assess whether that condition truly mattered. Every causal claim in history, that a railway, a war, an institution, or an idea made a difference, implicitly compares the actual world to a counterfactual one in which the supposed cause is absent. Counterfactual reasoning makes that comparison explicit and subjects it to rules: alter the antecedent minimally, keep the rest of the world as it plausibly would have been, and reason carefully toward the likely consequent. In its rigorous cliometric form, exemplified by Fogel's railroads study, the consequent is quantified as a social saving. But the general method is broader and conceptual, governed by criteria of minimal rewrite, plausibility, and explicit antecedent-consequent structure, and it underwrites causal inference throughout history, not only in its quantitative, economic variant.	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.