Gross state product (GSP). A measurement of a state's output; it is the sum of value added from all industries in the state. GSP is the state counterpart to the Nation's gross domestic product (GDP). Value added. The gross output of an industry or a sector less its intermediate inputs; the contribution of an industry or sector to gross domestic product (GDP). Value added by industry can also be measured as the sum of compensation of employees, taxes on production and imports less subsidies, and gross operating surplus.