An IO activity dataset is an Activity dataset corresponding to a column in a Make-use table or Direct requirements table. The term "IO" refers to input-output economics, the analytical framework from which these datasets originate.
In input-output economics, economic activities are represented through tables that systematically document the flows of goods and services between different sectors of an economy. Each column in a make-use table or direct requirements table represents a specific activity or activity class, and the IO activity dataset captures all the information contained in that column. This includes both the inputs required by the activity (the production factors consumed) and the outputs generated by the activity (the products produced).
These datasets typically represent the average, linear production function of an activity class. A production function describes the relationship between inputs and outputs, showing what production factors (inputs) are used to produce the Product outputs of the activity class. The "average" aspect indicates that the dataset reflects typical or mean values across all instances of activities within that class, rather than representing any single specific operation. The "linear" characteristic means that the relationship between inputs and outputs is proportional, so doubling the activity level would double both inputs and outputs.
Activity classes group similar economic activities together under common classifications such as ISIC (International Standard Industrial Classification of All Economic Activities). For example, an activity class might include all cement production facilities within a geographical region, and the corresponding IO activity dataset would show the average inputs (electricity, raw materials, labour) and outputs (cement, by-products) per unit of production across all those facilities.
IO activity datasets are fundamental building blocks in life cycle assessment databases, particularly those built using input-output methods or hybrid approaches that combine process-based and input-output data. They provide comprehensive coverage of economic activities and their resource requirements, making them valuable for capturing indirect and background processes in product systems.
