Extension card · m-Polar
m-Polar Fuzzy ELECTRE III (Akram and Adeel, 2023)
This is the form of ELECTRE III for situations where criteria are rated separately from several independent viewpoints. It derives weights from the data itself, and delivers the result as a single, clean outranking order that leaves no pair incomparable.
Base method
ELECTRE III →
Philosophy, mechanics, strengths and weaknesses are on the base method card; this card describes only the difference.
Data type (family)
m-Polar →
What this data type is, when to use it, how to write it in a cell: the family's full account is here.
What Changes from the Base Method?
Five things change; the idea of graduated comparison with indifference, preference and veto thresholds does not.
Cells. In crisp ELECTRE III every cell is a single number. Here every cell holds m numbers, one from each independent viewpoint: three if three experts assess it, four if four regions measure it. Each expert's own matrix is aggregated separately and then merged into a single m-polar matrix through a weighted-average operation (mFWAO).
Weights do not come from outside; they are derived from the data. In crisp ELECTRE III, weights come from the user; the method does not generate them. Here the opposite holds: DecisionMind reduces every cell of the merged matrix to a single score, using the average of the m poles, ratios these scores to the column total, and measures each criterion's discriminating power (divergence) with Shannon's (1948) entropy formula. A criterion with high discriminating power, one that genuinely separates the alternatives, receives a higher weight. The user does not supply a weight from outside; doing so would skip this step and disable the method's most important contribution.
Thresholds still come from outside. As in crisp ELECTRE III, the indifference (q), preference (p) and veto (v) thresholds for every criterion are taken from the user; unlike the entropy weights, these three are not derived from the data. Full concordance holds when the score difference is below q, none once it exceeds p, with a graduated zone in between. If the difference exceeds v, that criterion alone applies a veto.
Credibility and outcome mechanics. Crisp ELECTRE III pulls concordance down with discordance, then runs a two-way (ascending/descending) distillation and declares non-intersecting pairs incomparable. Here too a credibility index (β) is built: every criterion whose discordance exceeds its concordance pulls the concordance down. But the outcome mechanics differ. DecisionMind uses Li and Wang's (2007) net credibility method: each alternative's power to outrank the others (γ⁺) is added to its power to be outranked by them (γ⁻), the difference (γ) is taken, and the alternatives are ranked from highest to lowest on this single number.
DecisionMind fixes Shannon entropy weighting and Li-Wang net-credibility ranking for this extension. Combining the two differs from crisp ELECTRE III's two-way distillation-plus-intersection mechanics: because γ is a single real number for every alternative, the result is always a complete ranking. The incomparable pairs found in crisp ELECTRE III are not produced here.
How to Read the Output
What stays the same as the base method: an alternative's superiority comes not from being best on every criterion but from the graduated concordance-discordance calculation, and a single criterion that exceeds the veto threshold can block it on its own.
The difference lies here. Crisp ELECTRE III can leave some pairs incomparable, saying "the data could not separate these." This extension gives no such result; net credibility (γ) is always a real number, and the alternatives are ranked from top to bottom on this number. The weights, moreover, reflect the data's own discriminating power rather than the user's preference; where alternatives are very similar to one another on a criterion (low entropy separation), that criterion automatically receives a low weight, and the user cannot change this.
Thus instead of writing:
"m-Polar ELECTRE III chose x1 first because it is balanced across all the criteria"
the report should read:
"With weights derived from the data's own discriminating power (the heaviest criterion carrying 54 per cent), x1's net credibility comes out highest; this superiority should be read bearing in mind that the weights come from the data and that one criterion dominates"
When to Prefer This over the Base Method
Use this extension where a criterion's value genuinely comes from several independent sources (an expert panel, a region, a period) that should not be reduced to an early average. It is also directly suitable where the weights are wanted from the data's own discriminating power rather than the user's preference, that is, where an objective answer is sought to "which criterion genuinely separates the alternatives."
Crisp ELECTRE III's threshold condition still applies here: an expert opinion must exist to set the indifference, preference and veto thresholds. Where a criterion has a single source, forcing the m-polar structure is unnecessary; the family's crisp member should be used instead. Where seeing incomparable pairs separately matters, that is, where the information "the data could not separate these two" must not be lost, this extension is not sufficient; net credibility always produces a ranking.
Mistakes Specific to This Extension
Confusing m-polar with bipolar. m-Polar membership lies in [0,1]^m, m independent viewpoints; in the bipolar structure the second number is the opposite-direction effect, in [-1,0]. A bipolar dataset is not an m-polar dataset with m=2; the two are different value spaces.
Breaking the threshold order. Every criterion must satisfy 0 ≤ q < p ≤ v. Setting q=p empties the weak-preference band, and the graduated transition starts behaving like a switch (0/1), losing the method's main contribution.
Trying to supply a weight from outside. This extension generates its own weight through Shannon entropy; imposing the user's own preference weight disables the method's data-based weighting advantage, its principal difference from m-polar ELECTRE II.
Confusing a scalar weight with a pole-based weight. In this extension the entropy weight is scalar; the same number applies to every pole of a criterion. In m-polar ELECTRE II, by contrast, the weight is a separate vector per pole. Using one method's weighting step in place of the other's produces an incorrect weighted matrix.
Passing over flat (weakly discriminating) data unnoticed. If every alternative's score on a criterion sits very close to the others, entropy approaches 1, discriminating power approaches 0, and that criterion receives almost no weight. Whether the criterion itself is weak or the data merely looks flat should then be questioned.
The governing principle is this:
In m-polar ELECTRE III the weight comes from the data, the threshold from the user; confusing the two, or imposing the weight from outside, defeats the method's claim to objectivity. The result is always a complete ranking and produces no incomparable pair.
Cases
The first case is drawn from the literature: the hazardous-waste carrier selection example from Akram and Adeel's (2023) book chapter, set in Turkey. The second case is an illustrative construction.
1. Environment: Choosing among five hazardous-waste carrier firms (Akram and Adeel, 2023)
An industrial enterprise is evaluating five firms (x1-x5) for hazardous-waste transport, with three experts (logistics manager α=0.3654, sales coordination manager α=0.2885, environment-health-safety specialist α=0.3462) on five criteria (technical-administrative competence, service capacity, economic capacity, environmental safety, additional services); each criterion is measured through three sub-features (m=3), all "higher is better."
Once the three experts' matrices have been merged with mFWAO, the first row (x1) of the aggregated matrix reads: technical-administrative (0.6384; 0.4202; 0.7281), service capacity (0.6508; 0.498; 0.4697), economic capacity (0.5723; 0.9; 0.4965), environmental safety (0.438; 0.7136; 0.6102), additional services (0.5374; 0.5312; 0.6891). The method derives the weights from this merged matrix's score projection using Shannon entropy.
| Criterion | Technical-administrative | Service capacity | Economic capacity | Environmental safety | Additional services |
|---|---|---|---|---|---|
| Entropy weight | 0.0472 | 0.0912 | 0.0377 | 0.5377 | 0.2862 |
The environmental-safety criterion alone carries more than half the total weight (0.5377); this shows that the greatest separation among the firms falls on this criterion. The method then computes graduated concordance and discordance for every criterion using the book's own indifference, preference and veto thresholds (for example, environmental safety q=0.02, p=0.08, v=0.1), builds the credibility index, and ranks with Li-Wang net credibility.
| Rank | Firm |
|---|---|
| 1 | x1 |
| 2 | x2 |
| 3 | x4 |
| 4 | x5 |
| 5 | x3 |
The result reads as follows. x1 is markedly better than the others on environmental safety, the heaviest criterion; the entropy weighting making this criterion nearly the sole determinant largely explains x1's first place.
The enterprise's hesitation lies here. The book's own text (Table 5.11, p. 302) gives the order as x1 ≻ x2 ≻ x5 ≻ x4 ≻ x3; DecisionMind's engine, however, swaps x4 and x5 to produce x1 ≻ x2 ≻ x4 ≻ x5 ≻ x3. x1's first place and x3's last place agree across both calculations; only the middle x4-x5 order differs. Whether this small discrepancy comes from re-entering the book's Table 5.9 threshold values into the manifest or from a rounding difference in the net-credibility sum has been left to scientific review until it is settled (see approval notes).
In the report: "With weights derived from the data's own discriminating power (environmental safety 54 per cent), x1 comes out on top in net credibility and x3 at the bottom. The order between x4 and x5 differs between the DecisionMind engine and the source book's own table, and the choice between these two firms requires additional scientific verification."
Source: Akram, M., & Adeel, A. (2023). Multiple Criteria Decision Making Methods with Multi-polar Fuzzy Information, Chapter 5, §5.3 (pp. 293–302), Table 5.6 (entropy weights), Table 5.9 (thresholds), Table 5.11 (final ranking). The aggregated matrix (Table 5.7) and the weights are carried over from the book unchanged. DecisionMind's engine was run independently on this input; x1's and x3's extreme positions matched the book, the x4-x5 order did not (see approval notes).
2. Public-private partnership: Preliminary evaluation of three candidate investor consortia for a city hospital
A health ministry unit will carry out a preliminary evaluation of three investor consortia for a build-operate-transfer city hospital scheme. Four criteria apply: financial strength, construction experience, robustness of the operating plan, and commitment to community-health contribution (all four "higher is better"). Each criterion is measured through four independent scores (m=4) from four separate stakeholder groups (the ministry commission, an independent audit, local government, a patient-rights representative); three assessment experts compile these stakeholder scores separately.
The method merges the three experts' matrices, derives criterion weights with Shannon entropy, computes graduated concordance-discordance with the thresholds set for each criterion, and ranks with net credibility. Suppose the community-health contribution commitment criterion received the highest entropy weight, because the three consortia diverged from one another most on this criterion; financial strength, where all three scored close to one another, carried a low weight.
The unit's hesitation lies here. A low weight on the financial-strength criterion does not mean the criterion is unimportant; it means only that it is not discriminating among these three candidates. If a fourth candidate, a consortium markedly different in financial strength, is added to the process, this criterion's entropy weight is recalculated and can change.
In the report: "The community-health contribution commitment criterion received the highest entropy weight (0.41) as the criterion creating the greatest separation among the three candidates; the consortium that stands out with this weight is also strong in construction experience. The low weight on financial strength stems from its not being discriminating for these three candidates, and must be recalculated if the candidate set changes."
3. What Not to Do
In the waste-carrier example, ignoring the entropy weights and assuming the five criteria carry equal weight (20 per cent each) is the first mistake; this erases the information the data itself provides, that environmental safety is the criterion that actually discriminates here. The second mistake is ignoring the order discrepancy between DecisionMind and the source book on x4 and x5 and saying "both sources give the same result"; this discrepancy must be stated explicitly and left to scientific review. The third mistake is trying to impose the user's own weight preference from outside, as in the book (for instance, "in my view environmental safety should be 30 per cent"); this extension generates the weight itself through entropy and does not accept an outside weight.
Sources
For the formulas behind each step, the intermediate tables and citation formats, see the DecisionMind method page: decisionmind.app/library/mpf-electre-iii
Akram, M., & Adeel, A. (2023). Multiple Criteria Decision Making Methods with Multi-polar Fuzzy Information. Studies in Fuzziness and Soft Computing, vol. 430, Springer Nature. DOI: 10.1007/978-3-031-43636-9
Roy, B. (1978). ELECTRE III: Un algorithme de classement fondé sur une représentation floue des préférences en présence de critères multiples. Cahiers du CERO, 20(1), 3–24. (no DOI)
Chen, J., Li, S., Ma, S., & Wang, X. (2014). m-Polar fuzzy sets: An extension of bipolar fuzzy sets. The Scientific World Journal, 2014, 416530. DOI: 10.1155/2014/416530
Li, H.-F., & Wang, J.-J. (2007). An improved ranking method for ELECTRE III. Proceedings of the 2007 International Conference on Wireless Communications, Networking and Mobile Computing (WiCOM), 6659–6662. DOI: 10.1109/WICOM.2007.1634
Shannon, C. E. (1948). A mathematical theory of communication. Bell System Technical Journal, 27(3), 379–423. DOI: 10.1002/j.1538-7305.1948.tb01338.x