Inputoutputanalyse

Inputoutputanalyse, commonly known as input-output analysis, is a quantitative economic technique for studying the interdependencies between sectors of an economy. By constructing an input-output table, it records how the output of each sector serves as an input to every other sector, allowing researchers to trace how final demand propagates through the production system. It is used to assess economic multipliers, forecast the impact of changes in demand or technology, and analyze the structure of production and trade within an economy or a region.

The core of the method is the technology coefficient matrix A, where each element aij represents the amount of input from sector i required to produce one unit of output in sector j. With the total output vector x and final demand vector y, the relationship is x = (I − A)⁻¹ y, where I is the identity matrix. The matrix (I − A)⁻¹, known as the Leontief inverse, quantifies both direct and indirect effects of final demand changes on sectoral outputs. The framework can be extended to multi-region settings and to environmental applications, yielding regional input-output analysis and environmental input-output analysis (EIOA), which link economic activity to resource use and emissions.

Applications include estimating the economic impact of policy changes, technological shifts, infrastructure programs, and trade moves; evaluating regional development, supply-chain resilience, and environmental footprints. Limitations arise from requiring fixed input coefficients, linear production relationships, and static, snapshot data; results can be sensitive to sector classifications and data quality. Despite these caveats, input-outputanalyse remains a foundational tool for descriptive and prospective analysis in economics and regional planning.