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.
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Method map
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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
- 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.
- Assumes full compensation — a strong score on one criterion can offset a weak score on another.
Sources
- Fishburn, P. C. (1967). Additive utilities with incomplete product sets: Application to priorities and assignments. Operations Research DOI: 10.1287/opre.15.3.537 ↗
How to cite this page
ScholarGate. (2026, June 2). Weighted Sum Model (Simple Additive Weighting). ScholarGate. https://scholargate.app/en/decision-making/wsm
Which method?
Set this method beside its closest kin and read them side by side — the library lays the books on the table; the choice is yours.
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