Social Life Cycle Assessment

S-LCA borrows the four-phase ISO LCA structure of goal and scope, inventory, impact assessment, and interpretation, but its impact categories concern people rather than the biophysical environment. Instead of emissions and resource use, it assesses subcategories like fair wages, child labor, health and safety, and community engagement, organized by stakeholder groups. A key methodological difference is that environmental impacts scale with physical throughput, whereas social conditions reflect organizational conduct, so S-LCA introduces activity variables such as worker-hours to relate social findings to the functional unit. The two are designed to be complementary parts of a broader life-cycle sustainability assessment.

A performance reference point is a benchmark against which an inventory indicator is judged, such as a legal minimum wage, an International Labour Organization convention, or a sector average. It matters because raw social data are not interpretable on their own: a wage of a given amount is good or bad only relative to local cost of living and standards. By comparing the measured value to the reference point, S-LCA turns the indicator into a normalized social-impact score signaling better or worse than acceptable. Because the reference point embeds a value judgment about what is acceptable, its choice strongly shapes the result and must be made transparently.

Environmental flows scale naturally with how much is produced, but social conditions are properties of how organizations behave, not of physical output, so they cannot be summed across processes the same way. Activity variables solve this by weighting each process according to a measure of human involvement, most commonly worker-hours, on the premise that social impacts on workers accumulate with the labor a process demands. Normalizing these variables across the life cycle yields weights that let process-level social scores be aggregated and attributed to the product. The activity variable is therefore the device that connects conduct-based social indicators to the functional unit.