Chapter 07 · Materials & footprintsLife Cycle Assessment & Product Footprinting
Weighting
Definition
Weighting is an optional assessment step that applies relative importance values to different impact categories.
References
This reference provides supporting context for how “Weighting” is defined and used.
Overview
What it means in practice
Weighting should be read as a life-cycle and product-footprinting term. Its meaning depends on the study goal, scope, data source, method and interpretation context.
In practice, users should state the boundary, baseline, data source and method. That keeps weighting useful as a reference without overstating the result.
Why it matters
Weighting matters because footprinting language determines what is counted, compared and communicated. Clear definitions make assumptions visible and reduce the risk of misleading comparisons.
Common misconception
A common error is to treat Weighting as a neutral technical label. The stronger approach is to explain the modelling choice and how it changes the result.
Review questions
What boundary, baseline or comparison is being used? What evidence supports the term? What assumption or limitation would change how a reader interprets it?
How it is used
Designers, manufacturers, procurement teams, life-cycle practitioners and waste managers use “Weighting” in product design, procurement, footprinting, material selection, production and end-of-life decisions.
In each case, the user should state the product system, life-cycle stages, functional unit, geography, timeframe and measurement method; otherwise, the same term may be applied to materially different situations. In this context, it refers to an optional assessment step that applies relative importance values to different impact categories.