LCA stands for Life Cycle Assessment. For example, it is used to find the best process to reduce CO2. LCA is defined as ISO14040.
It assess burdens of all processes bringing materials, making production, transportation and so on.
Estimate burdens of input and output for each step. Then calculate the sum of total input and output.
Because defining "all" process depends on the analyst, checking the range of "all" is important for us.
Some books say that Input-Output Analysis is used for LCA. But I do not know how relationship of industries is used for LCA.