Lesson 5: Stages of a Life-Cycle Assessment

In this lesson, we explore the essential stages of a Life-Cycle Assessment (LCA) and their significance.


  • The goal and scope definition is the initial stage of an LCA, where the purpose, boundaries, and focus of the study are established.
  • The goal statement specifies the intended use of the LCA study, and the scope defines the system boundary.
  • The scope includes the functional unit, which is a measurable reference quantity of the product or service under study, and the system boundary, which determines the life cycle stages to be considered.
  • A well-defined goal and scope statement is essential for ensuring that the LCA study is relevant, transparent, and robust.


  • The inventory analysis is the second stage, involving the collection and quantification of data on the inputs and outputs of the system under study.
  • This stage identifies the life cycle stages, activities, and inputs and outputs associated with the product or service under study.
  • The results are typically presented as a life cycle inventory (LCI), providing a comprehensive list of environmental inputs and outputs.
  • Careful consideration of the system boundary, data quality, and allocation methods is essential for a robust inventory analysis.


  • Impact assessment is the third stage, evaluating the environmental impacts of the product or service under study.
  • It categorizes and characterizes the inventory data into potential environmental impacts, such as global warming or acidification.
  • Characterization factors quantify the magnitude and significance of each environmental impact category.
  • Careful consideration of data quality and uncertainty is crucial in the impact assessment.


  • Interpretation is the final stage, where the results of the LCA study are analyzed and communicated to stakeholders.
  • This stage evaluates the findings in the context of the goal and scope, drawing conclusions and recommendations.
  • It is critical in communicating results clearly and facilitating decision-making processes.
  • Interpretation also involves considering data quality, uncertainty, sensitivity analysis, and stakeholder values and preferences.


  • A well-defined goal and scope set the foundation for a robust LCA study.
  • Inventory analysis provides a comprehensive list of environmental inputs and outputs, essential for subsequent stages.
  • Impact assessment evaluates the environmental significance of identified impacts.
  • Interpretation communicates results clearly and guides decision-making processes.
  • Understanding these stages is vital for conducting a meaningful LCA, making informed decisions, and contributing to sustainability efforts.
Go back