Range-Adjusted Measure of Inefficiency
DEA-RAM (Range-Adjusted Measure of Inefficiency) is a dea multi-criteria decision-making (MCDM) method introduced by Cooper, W. W. Park, K. S. Pastor, J. T. in 1999. 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
RAM is a non-radial DEA model using range-adjusted weights for input/output slacks. Unlike CCR/BCC (radial), RAM accounts for all slacks simultaneously. ρ=1 means fully efficient; ρ<1 quantifies normalised distance to frontier. Requires VRS (Σλ=1). Insensitive to units of measurement.
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.
Common pitfalls
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Sources
- 1.Cooper, W. W., Park, K. S., Pastor, J. T. (1999). RAM: A Range Adjusted Measure of Inefficiency for Use with Additive Models, and Relations to Other Models and Measures in DEA. Journal of Productivity Analysis
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ScholarGate. (2026, June 2). DEA-RAM. ScholarGate. https://scholargate.app/decision-making/dea-ram