手法を比較

	Agricultural Household Model	Gross Margin Analysis
分野	Food Agriculture Studies	Food Agriculture Studies
系統	Regression model	Process / pipeline
提唱年	1986	1979
提唱者	Inderjit Singh, Lyn Squire & John Strauss	C. S. Barnard & J. S. Nix (farm planning tradition)
種類	Structural production-consumption household model with separability testing	Enterprise margin pipeline (output minus variable costs)
原典	Singh, I., Squire, L., & Strauss, J. (Eds.). (1986). Agricultural Household Models: Extensions, Applications, and Policy. Baltimore: Johns Hopkins University Press for the World Bank. ISBN: 9780801932489	Barnard, C. S., & Nix, J. S. (1979). Farm Planning and Control (2nd ed.). Cambridge: Cambridge University Press. ISBN: 9780521296045
別名	Farm Household Model, Singh-Squire-Strauss Model, Non-Separable Household Model, Agricultural Household Production-Consumption Model	Enterprise Gross Margin, Gross Margin Budgeting, Contribution Margin Analysis (Farm), Variable-Cost Margin Analysis
関連	3	3
概要	The agricultural household model treats the farm household as a single unit that is simultaneously a producer and a consumer, choosing how much to grow, how much labour to hire or supply, and how much to consume — decisions that ordinary firm theory and consumer theory treat as separate. Synthesised in Singh, Squire, and Strauss's 1986 World Bank volume, the model's central result is conditional: when all markets (especially for labour) function perfectly, the household's problem is recursive — it maximises farm profit first and then spends that profit like any consumer, so production decisions are independent of preferences. But when markets fail, the two sides fuse: a shadow wage replaces the market wage and household composition begins to drive production. Whether that separation holds is an empirical question, and Benjamin's 1992 Econometrica test is the canonical way to answer it.	Gross margin analysis is the workhorse of farm management planning: for each enterprise on a farm it computes the gross margin — gross output minus the variable costs directly attributable to that enterprise — usually expressed per hectare, per head, or per activity unit. Rooted in the British farm-planning tradition of Barnard and Nix and a fixture of standard farm management texts, the gross margin deliberately stops short of fixed and overhead costs. That makes it the natural currency for comparing enterprises and planning the farm: because fixed costs are largely common to all enterprises in the short run, ranking and combining enterprises by their gross margins per unit of the scarce resource is the quickest route to a more profitable farm plan.