In life cycle assessment, what determines which stages are included in the assessment (e.g., cradle-to-grave, cradle-to-gate)?

• A. Boundaries define geographic scope.
• B. Boundaries are defined by the available data.
• C. Boundaries determine which life cycle stages are included in the assessment.
• D. Boundaries are fixed and cannot be adjusted.

Answer: (C)

In life cycle assessment, the stages you include are determined by the system boundaries you set. Those boundaries define the whole scope of the study, so choosing cradle-to-grave includes use and end-of-life, while cradle-to-gate stops at the factory gate and excludes phases after production. The boundaries are chosen to match the goal of the analysis and what makes sense to model, which is why they directly decide which life cycle stages are included. Data availability or geographic scope can influence how you implement the boundary, but they don’t by themselves define which stages are included. Boundaries can be adjusted to fit the study as needed.