Social Accounting Matrix
Also known as: SAM, Social Accounting Framework, SAM Multiplier Model
A social accounting matrix (SAM) is a square, double-entry table that records all transactions among the production sectors, factors of production, institutions (households, firms, government), and the rest of the world in an economy for a given year. It extends the input-output table by closing the circular flow of income — connecting how value added becomes factor income, factor income becomes household income, and household income becomes demand — so that every account's receipts (its row) exactly equal its expenditures (its column).
Key highlights
- Closes the circular flow of income, capturing induced consumption effects that input-output multipliers omit.
- Disaggregates households and factors, enabling explicit analysis of income distribution and incidence by socioeconomic group.
- Imposes double-entry balance, forcing reconciliation of disparate data sources into one consistent framework.
- Serves as the standard calibration database for computable general equilibrium models, bridging accounting and behavioral analysis.
Intuition
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How it works
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When to use it
Use a SAM when you need an economy-wide, internally consistent picture of income generation and distribution — not just production linkages — and you want to trace how an exogenous injection (export demand, government transfer, foreign aid, a new investment) affects sectoral output, factor incomes, and household groups including induced consumption effects. SAMs are the standard tool for distributional impact analysis and the mandatory database for calibrating computable general equilibrium models. SAM multiplier analysis assumes fixed average expenditure propensities and excess capacity, so like input-output analysis it is a short-run, demand-driven, price-free model; when prices and substitution matter, the SAM should instead be used to calibrate a CGE model.
Strengths & limitations
- Closes the circular flow of income, capturing induced consumption effects that input-output multipliers omit.
- Disaggregates households and factors, enabling explicit analysis of income distribution and incidence by socioeconomic group.
- Imposes double-entry balance, forcing reconciliation of disparate data sources into one consistent framework.
- Serves as the standard calibration database for computable general equilibrium models, bridging accounting and behavioral analysis.
- Multiplier analysis assumes fixed average expenditure propensities and idle resources, so prices and substitution are absent.
- Constructing and balancing a SAM is data-intensive and requires reconciling sources of differing quality, often via estimation techniques.
- Results are sensitive to which accounts are designated endogenous versus exogenous, a modeling choice that changes the multipliers.
- Like input-output, it is a base-year snapshot and becomes outdated as economic structure shifts.
Common pitfalls
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Applications
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Frequently asked
How does a SAM differ from an input-output table?
An input-output table records only inter-industry flows and stops at value added. A SAM is square and balanced and additionally records how value added becomes factor income, how factor income becomes institutional (household, firm, government) income, and how that income is spent — closing the circular flow. As a result SAM multipliers include induced consumption effects that input-output multipliers, which treat household income as exogenous, leave out.
What does it mean to balance a SAM, and how is it done?
Balancing means making every account's row total (receipts) equal its column total (expenditures), as double-entry accounting requires. Raw data assembled from national accounts, surveys, and trade statistics rarely balance, so analysts use estimation procedures — most commonly the RAS biproportional method or cross-entropy minimization — to adjust the cells minimally while satisfying all row and column constraints.
Why is a SAM needed to build a CGE model?
A computable general equilibrium model requires a consistent benchmark dataset of all transactions among agents in a base year to calibrate its parameters and ensure the model replicates the observed economy at the starting point. A balanced SAM provides exactly this: it is the empirical accounting skeleton on which the CGE's behavioral equations (production functions, demand systems, market clearing) are hung.
Sources
- 1.Pyatt, G., & Round, J. I. (Eds.). (1985). Social Accounting Matrices: A Basis for Planning. Washington, DC: The World Bank.ISBN 9780821305508
- 2.Stone, R. (1962). A Social Accounting Matrix for 1960. A Programme for Growth, Vol. 2. London: Chapman and Hall.ISBN 9780412208300
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ScholarGate. (2026, June 22). Social Accounting Matrix. ScholarGate. https://scholargate.app/economics/social-accounting-matrix