Extension card · Hesitant
Probabilistic hesitant EDAS (manifest name: extended hesitant linguistic EDAS)
This is the form of EDAS in which more than one plausible value for a criterion is carried in a single cell together with its probability of occurrence. Every cell is reduced to a probability-weighted expected value in the method's first step, and the rest of the calculation runs on that value.
Base method
EDAS →
Philosophy, mechanics, strengths and weaknesses are on the base method card; this card describes only the difference.
Data type (family)
Hesitant →
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?
Four things change; the logic of locating a position relative to the average does not.
Cells. In classical EDAS every cell is a single number. Here every cell consists of more than one possible value, each given with its own probability: {(γ₁,p₁), (γ₂,p₂), ...}, and the probabilities cannot sum to more than 1. An assessment such as "this supplier's delivery performance is 0.6 with even odds and 0.8 with even odds" corresponds to this structure.
Early reduction to an expected value. Before the average is even built, the kernel reduces every cell, at the very first step of the calculation, to a single number: the expected value found by multiplying every possible value by its own probability and summing. The founding paper's possibility-degree ordering and BUM-weighted aggregation are not implemented here; the kernel instead takes the column's arithmetic mean.
The average solution and deviations. The average is the arithmetic mean, across each column, of these expected values. Positive and negative deviation are computed by the same rule as in classical EDAS: above the average is favourable for a benefit criterion, below the average is favourable for a cost criterion.
Result and defuzzification. Defuzzification sits at the start, not at the end. Every cell's more-than-one possible value descends to a single expected value at the calculation's first step, and the spread among those values feeds into none of the subsequent steps.
DecisionMind fixes the expected-value function and this early-reduction order in this extension. Weights are taken from outside as crisp numbers; the method does not generate weights.
How to Read the Output
The appraisal score is read exactly as in classical EDAS: a position relative to the set's own average, not a percentage or a probability. The difference is this: beneath the score there is no longer a probability distribution, only that distribution's single expected value. Two alternatives can reach the same expected value through very different distributions; one may arrive at it from a narrow range with high probability, the other from a wide range with uncertain probabilities. The expected value does not show this difference.
Thus instead of writing:
"PHF-EDAS carries probabilistic uncertainty all the way through, so the result is more reliable"
the report should read:
"Every cell's possible values have been reduced to a single expected value at the very first step of the calculation; the resulting score is computed from these expected values, and the width of the distribution is not reflected in the score"
When to Prefer This over the Base Method
This extension is suitable when more than one plausible value exists for a criterion assessment, and the probability of each of these values occurring is known. If the probability is unknown, and only that more than one value is plausible is known, the classical hesitant structure and an EDAS extension suited to it should be sought instead. For a single measured criterion, classical EDAS is sufficient; opening up a single measurement into a probabilistic set adds no information. If experts give the term linguistically and the possibility-degree ordering itself is wanted (the EHFLTS and ELCOWA mechanism in the founding paper), this is a capability DecisionMind's current engine does not offer, and this limitation should be stated in the report.
Mistakes Specific to This Extension
Confusing the kernel with the founding paper's linguistic-possibility method. The founding paper works over a set of linguistic terms and a possibility degree; DecisionMind's kernel works over numerical (γ,p) pairs and an expected value. Though called by the same name, the two are mathematically different; the report must state clearly which one was used.
Letting the probabilities in a cell sum to more than 1. If the probabilities in a cell exceed 1, the expected value is no longer an expected value; the input must not be fed into the calculation unchecked.
Weighting the distribution equally, as with a hesitant set without probabilities. Giving every possible value an equal share instead of its real probability erases the one contribution the probabilistic hesitant structure makes, namely bringing the likelihood of occurrence into the information.
The "more sophisticated" fallacy. A probabilistic input does not automatically mean a more accurate result than classical EDAS; because of the early reduction, its contribution lies only in how the input is aggregated.
The governing principle is this:
In PHF-EDAS, every cell's possible values are reduced to a single expected value at the very first step, before the average is even built. This is not the founding paper's linguistic-possibility mechanism; the report must state clearly which mechanism was used.
Cases
The founding paper's (Feng, Wei and Liu, 2018) numerical example is built over a set of linguistic terms and a possibility degree, and because DecisionMind's kernel does not implement this mechanism, the paper's table cannot be carried over here. The first case is therefore DecisionMind's validation example, and it is faithful to the formula chain the kernel actually runs (expected value, average, deviation, normalisation). The second case is an illustrative construction.
1. Illustrative example: Three alternatives assessed on three criteria (DecisionMind validation example)
Three alternatives are assessed on three criteria (C1, C2 higher is better; C3 lower is better) with probabilistic hesitant values; every cell carries two possible values, at equal probability. Weights: C1=0.40, C2=0.35, C3=0.25.
| Alternative | C1 | C2 | C3 (cost) |
|---|---|---|---|
| A1 | {0.6 (0.5); 0.8 (0.5)} | {0.4 (0.5); 0.6 (0.5)} | {0.5 (0.5); 0.7 (0.5)} |
| A2 | {0.7 (0.5); 0.9 (0.5)} | {0.5 (0.5); 0.7 (0.5)} | {0.3 (0.5); 0.5 (0.5)} |
| A3 | {0.5 (0.5); 0.7 (0.5)} | {0.6 (0.5); 0.8 (0.5)} | {0.4 (0.5); 0.6 (0.5)} |
The method reduces every cell to an expected value (A1 C1: 0.6×0.5+0.8×0.5=0.7, and so on), reverses direction on C3, builds the column average over these expected values, and applies the remaining steps of classical EDAS.
| Alternative | Appraisal score | Rank |
|---|---|---|
| A2 | 1.000 | 1 |
| A3 | 0.508 | 2 |
| A1 | 0.000 | 3 |
The result reads as follows. A2's expected value on C1, the heaviest criterion, (0.8) sits above the average (0.7). On the cost-oriented C3, once reversed, it also sits below the average, that is, in its favour. Being advantaged on two heavy criteria at once puts it first. A1 sits in exactly the opposite position on both criteria and finishes last.
The decision's hesitation: if C2's weight is raised from 0.35 to 0.60, and C1's weight lowered from 0.40 to 0.25 and C3's from 0.25 to 0.15, the ranking reverses. When DecisionMind's engine is rerun independently with these new weights, A3 comes out first at 0.863 and A2 second at 0.829. This shows how sensitive the A2-A3 ranking is to the relative weight of C1 against C2.
In the report: "With the given weights (C1=0.40, C2=0.35, C3=0.25), A2 sits in the most favourable position relative to the set's average (1.000). If C2's weight is raised markedly (C2=0.60), the ranking reverses and A3 moves ahead; the weight distribution should therefore be separately justified."
Source: DecisionMind's PHF-EDAS engine validation example. Because the founding paper's (Feng, Wei and Liu, 2018) numerical example is built over a set of linguistic terms and a possibility-degree mechanism that the kernel does not implement, the table has been constructed synthetically, faithful to the kernel's real formula chain. The appraisal scores and weight scenario were verified by this card's author, running DecisionMind's engine (scripts/method_runner.py PHF-EDAS) independently.
2. Care home: A care-home chain's choice of maintenance-service provider for a new branch
A care-home chain will choose one of three outsourced maintenance-service providers for a branch it is opening. The criteria are: expected resident satisfaction, service cost, and staff turnover rate; the latter two are "lower is better." The chain has gathered each provider's performance data from past contracts as a probabilistic hesitant value, together with the probability of occurrence of different shift scenarios.
The method finds every provider's expected value on the three criteria, measures its favourable and unfavourable deviation from the column average, combines these with the weights, and totals them into a single appraisal score. Suppose the provider with the lowest service cost is also the one with the highest staff turnover rate, and still comes out first, because cost is weighted more heavily than turnover.
The chain's hesitation: a long-term contract with a provider whose staff turnover rate is high can disrupt continuity of care. The chain should not leave this risk to the appraisal score, but limit it through a separate pre-screening tied to a turnover-rate ceiling.
In the report: "The priority order has been shaped by the provider that sits below the average, and therefore in its favour, on this criterion because of the high weight given to service cost. A separate turnover-rate ceiling is recommended for providers above the average on staff turnover."
3. What Not to Do
In the illustrative example, inventing arbitrary probabilities (say, 0.9 and 0.1) instead of equal ones for A1's two possible values on C1 (0.6 and 0.8) distorts the expected value unrealistically; every probability must come from its own source. The second error, in the care-home example, is assuming that the founding paper's possibility-degree ordering has been applied; the kernel does not run this mechanism, it only computes the expected value. The third error is disregarding that C3 is a cost criterion and assessing its expected value as a benefit; this mistakenly rewards the most expensive alternative.
Sources
For the formulas behind each step, the intermediate tables and citation formats, see the DecisionMind method page: decisionmind.app/library/phf-edas
Feng, X., Wei, C., & Liu, Q. (2018). EDAS method for extended hesitant fuzzy linguistic multi-criteria decision making. International Journal of Fuzzy Systems, 20(8), 2470–2483. DOI: 10.1007/s40815-018-0504-5
Xu, Z., & Zhou, W. (2017). Consensus building with a group of decision makers under the hesitant probabilistic fuzzy environment. Fuzzy Optimization and Decision Making, 16(4), 481–503. DOI: 10.1007/s10700-016-9257-5
Zhang, S., Xu, Z., & He, Y. (2017). Operations and integrations of probabilistic hesitant fuzzy information in decision making. Information Fusion, 38, 1–11. DOI: 10.1016/j.inffus.2017.02.001
Torra, V. (2010). Hesitant fuzzy sets. International Journal of Intelligent Systems, 25(6), 529–539. DOI: 10.1002/int.20418
Keshavarz Ghorabaee, M., Zavadskas, E. K., Olfat, L., & Turskis, Z. (2015). Multi-criteria inventory classification using a new method of evaluation based on distance from average solution (EDAS). Informatica, 26(3), 435–451. DOI: 10.15388/Informatica.2015.57