Extension card · q-Rung Orthopair
q-Rung orthopair MOORA
This is the form of MOORA for situations where an expert assigns a judgement both strong support and a strong reservation at once, and the sum of the two exceeds the intuitionistic or Pythagorean bound. The ratio system runs on this pair and descends to a single net score.
Base method
MOORA →
Philosophy, mechanics, strengths and weaknesses are on the base method card; this card describes only the difference.
Data type (family)
q-Rung Orthopair →
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?
Cells. In crisp MOORA every cell is a single number. Here every cell is a pair: support μ, rejection ν; the sum of their q-th powers cannot exceed 1. The user does not choose q; DecisionMind runs this family at q = 3, and this value is fixed. Criterion weights come from outside as crisp numbers.
Scale equalisation. Crisp MOORA divides the cell value directly by the column magnitude. QR-MOORA first reduces each pair to a single score. The score is support cubed minus rejection cubed (μ³ − ν³, because q = 3); since this value can fall between −1 and 1, 1 is added to shift it. The shifted score is then normalised exactly as in crisp MOORA, by dividing by the root of its own column magnitude. For a cost criterion the pair is not reversed; the direction difference is instead carried by sign in the subsequent summing-subtracting step.
Score and ratio system. The normalised shifted scores are weighted; the sum over "more is better" criteria has the sum over "less is better" criteria subtracted from it. This is exactly the same operation as crisp MOORA's ratio system; the only difference is that the input has already been reduced to a μ³ − ν³ score beforehand.
Result and defuzzification. The score-extraction step is itself the defuzzification, and it happens at MOORA's first step, not at the end. DecisionMind also genuinely computes the reference-point approach for this family. A reference point is built from each criterion's best normalised score, and each alternative's largest weighted deviation from that point (Chebyshev distance) is produced as a separate score. The final ranking and the reported score, however, rest solely on the ratio system; the reference-point score stands as an auxiliary, optional cross-check.
DecisionMind fixes q = 3, the score function and vector normalisation for classical QR-MOORA. Weights are taken from outside as crisp numbers; the method does not generate weights.
How to Read the Output
The output is a net score and a rank, as in crisp MOORA; it is read the same way. The difference is this. This score rests on the cube difference between a judgement's support and rejection degrees, and the tension between the two stays hidden beneath the score. A criterion on which the expert has given both high support and high reservation appears in the report only as a single net difference.
Thus instead of writing:
"Because q-rung MOORA models uncertainty, the result is more accurate"
the report should read:
"The criteria on which the expert gave both strong support and strong reservation have been flagged separately; the net score has turned out sensitive to the weight of these criteria"
When to Prefer This over the Base Method
Use this extension when an expert gives a judgement both strong support and a strong reservation at once, and this pair exceeds both the intuitionistic and the Pythagorean bound. Which pair exceeds which bound is shown by the short decision rule on the q-rung data-type card. If the pair already fits within the intuitionistic or Pythagorean bound there is no need to raise q; in DecisionMind, q is in any case not user-adjustable, it comes bundled with the method itself.
Converting an already-measured criterion into this form is wrong. In DecisionMind the table must be of a single type throughout. The exit condition is the same as for crisp MOORA: if no compromise is acceptable on one criterion, this extension too is compensatory and will not eliminate anything below a threshold.
Mistakes Specific to This Extension
Entering data without checking the constraint. In every cell, the sum of the cubes of the support and rejection degrees cannot exceed 1. This check is made before the calculation, not after.
Changing the score function while expecting the same result. DecisionMind fixes the μ³ − ν³ score. A different score can give a different order; which score was used must be stated in the report.
Mistaking the reference-point score for the final ranking. In this family the reported ranking rests on the ratio system; the reference-point score is a separate, optional cross-check and is not, on its own, the final result.
Defuzzifying first and then running crisp MOORA. Disregarding support and rejection degrees and calculating with only an averaged number is not this extension; the tension is erased at the very first step.
The governing principle is this:
q-Rung orthopair MOORA exists to carry the tension between support and rejection through to the ratio system. Any application that fails to check the constraint, or changes the score function without declaring it, erases this extension's own contribution.
Cases
The first case is DecisionMind's validation example. Yager (2017) is the founding source for the q-rung orthopair fuzzy set but contains no decision table specific to MOORA; DecisionMind has therefore built a small, hand-traceable table faithful to the same formulas. The second case is an illustrative construction.
1. Illustrative example: Three alternatives, three criteria (DecisionMind validation example)
Three alternatives are evaluated on three criteria. The first two criteria are "more is better," the third is "less is better." The calculation runs with q = 3.
| Alternative | C1 (more is better) | C2 (more is better) | C3 (less is better) |
|---|---|---|---|
| A1 | (μ=0.70; ν=0.40) | (μ=0.50; ν=0.50) | (μ=0.60; ν=0.50) |
| A2 | (μ=0.80; ν=0.30) | (μ=0.60; ν=0.40) | (μ=0.40; ν=0.60) |
| A3 | (μ=0.60; ν=0.50) | (μ=0.70; ν=0.40) | (μ=0.50; ν=0.50) |
| Weight | 0.40 | 0.35 | 0.25 |
The method extracts the μ³ − ν³ score for every cell, shifts the score and normalises it by column magnitude. It then weights the result and subtracts the sum over the "less is better" criterion from the sum over the "more is better" criteria.
| Alternative | MOORA score | Rank |
|---|---|---|
| A2 | 0.3431 | 1 |
| A3 | 0.2729 | 2 |
| A1 | 0.2440 | 3 |
The result reads as follows. A2 holds the highest support and the lowest rejection degree on all three criteria; it carries the best share on the "more is better" criteria and the lowest share on the "less is better" criterion.
The board's hesitation does not lie in A2's first place; it lies in the width of A2's lead. If the C1 weight is pulled from 0.40 to 0.10 and the C2 weight raised from 0.35 to 0.65 (C3 held at 0.25), A3 moves ahead of A2 with 0.3197 against A2's 0.3181. Once the weight given to C1 falls below a certain threshold, A2's strong position on this criterion no longer suffices to carry the ranking.
In the report: "With the weights given, A2 holds the highest net score (0.3431). When the C1 weight is lowered to 0.10, A3 takes first place; this shows that A2's superiority rests on its strong position on C1."
Source: DecisionMind's QR-MOORA manifest, validation example. The score function and the constraint rest on Yager's (2017) definition of the q-rung orthopair fuzzy set; since the founding source gives no decision table specific to MOORA, the table has been built by this card's author faithfully to the formulas. The MOORA scores and the weight-sensitivity result were independently recomputed by this card's author with the same algorithm, matching the kernel code exactly.
2. Freight: A firm's choice of international shipping carrier
A firm will choose among three international freight carriers. Three criteria are used: delivery speed, customs and damage risk (the latter "less is better"), and price competitiveness. The logistics team reports both strong support and strong reservation for delivery speed, because the fastest carrier is also the one with a disputed damage record; this duality pushes the support-rejection pair over both the intuitionistic and the Pythagorean bound.
The method scores and normalises the three carriers, weights the result and computes the ratio-system score. Suppose the carrier with the highest delivery speed also carries the highest risk score; it still comes out first, because the speed weight exceeds the risk weight.
The firm's hesitation: if the risk weight is raised, that is, if the firm regards damage risk as more critical than speed, the ranking may change. This sensitivity should be reported not through a single weight scenario alone but by showing at what point the ranking turns as the weight is raised.
In the report: "With the weights given, the carrier with the highest delivery speed comes first on the net score; the point at which this ranking changes as the risk weight is raised has also been shown."
3. What Not to Do
In the illustrative example, disregarding the rejection degree and running crisp MOORA on the support degrees alone makes A2's lead appear at a different magnitude than its true value. The second error is adding a pair to the table that fails the q = 3 constraint; for instance a pair with support 0.95 and rejection 0.80 has cubes summing to more than 1, and the calculation starts from an invalid point. The third error is reporting the score coming out of the reference-point step as the final ranking; in this family the reported ranking rests on the ratio system.
Sources
For the formulas behind each step, the intermediate tables and citation formats, see the DecisionMind method page: decisionmind.app/library/qr-moora
Brauers, W. K. M., & Zavadskas, E. K. (2006). The MOORA method and its application to privatization in a transition economy. Control and Cybernetics, 35(2), 445–469. (no DOI)
Yager, R. R. (2017). Generalized orthopair fuzzy sets. IEEE Transactions on Fuzzy Systems, 25(5), 1222–1230. DOI: 10.1109/TFUZZ.2016.2604005
Liu, P., & Wang, P. (2018). Some q-rung orthopair fuzzy aggregation operators and their applications to multiple-attribute decision making. International Journal of Intelligent Systems, 33(2), 259–280. DOI: 10.1002/int.21927