MCDMDecision-makingRankingMath steps
Weighted Sum Model (Simple Additive Weighting)
WSM (Weighted Sum Model (Simple Additive Weighting)) is a ranking multi-criteria decision-making (MCDM) method introduced by Fishburn, P. C. in 1967. It turns a decision matrix of alternatives scored on multiple criteria into a structured, reproducible result.
Key highlights
- Follows a transparent, reproducible computational procedure that can be audited step by step.
- Handles multiple criteria of differing scales and units within a single decision matrix.
Intuition
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How it works
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When to use it
WSM (SAW): score = Σ w_j × r_ij. Higher score means the alternative is closer to ideal across all weighted criteria. Simplest and most transparent MCDM method — appropriate when criteria are commensurate or pre-normalised.
Strengths & limitations
Strengths
- Follows a transparent, reproducible computational procedure that can be audited step by step.
- Handles multiple criteria of differing scales and units within a single decision matrix.
Limitations
- Assumes full compensation — a strong score on one criterion can offset a weak score on another.
Common pitfalls
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Sources
- 1.Fishburn, P. C. (1967). Additive utilities with incomplete product sets: Application to priorities and assignments. Operations Research
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Cite this page
ScholarGate. (2026, June 2). WSM. ScholarGate. https://scholargate.app/decision-making/wsm