Extension card · q-Rung Orthopair
q-Rung Orthopair ARAS (Mishra & Rani, 2023)
This is the form of ARAS for situations where criterion scores are given as a judgement's support and rejection degrees, and the sum of these two degrees exceeds the intuitionistic and Pythagorean boundary. It still expresses the utility degree as a percentage ratio against a hypothetical optimal alternative.
Base method
ARAS →
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?
Four things change; the utility-degree logic does not.
Cells. In crisp ARAS every cell is a single number. Here every cell is a pair: a support degree (μ) and a rejection degree (ν). The sum of these two degrees raised to the q-th power cannot exceed 1. The user does not choose q; it comes bundled with the method's own definition, and DecisionMind holds it fixed. Weights are still supplied from outside as single numbers; the method does not generate weights.
Scale equalisation. Crisp ARAS inverts the cost criterion and divides every column by its own total. No such division happens here, because the support and rejection degrees already lie between 0 and 1 and need no further step to become comparable across columns. For a cost criterion the method inverts the pair instead: the support and rejection degrees swap places. Every criterion is then read in the benefit direction.
Optimal alternative and aggregation. As in crisp ARAS, a hypothetical optimal alternative is built here too: a row made of the highest support and lowest rejection pair observed on each criterion. A weighted aggregation across criteria is then carried out for both the real alternatives and this optimal row. Unlike crisp ARAS's plain sum, this aggregation uses a q-Rung aggregation rule that processes the support and rejection degrees together, and the result is again a single pair (support, rejection).
Score and defuzzification. The aggregated pair is reduced to a single score between 0 and 1. DecisionMind specifically uses a score rule that stays within 0 and 1, to avoid a sign problem that could otherwise arise from q's negative powers, rather than a form of the score that could come out negative. Every real alternative's score is then divided by the optimal alternative's score. This ratio is the utility degree (K) and, as in crisp ARAS, it is read as a percentage benefit against the optimal alternative, between 0 and 1.
DecisionMind holds q and the score rule fixed for this method. Weights are taken from outside as single numbers.
How to Read the Output
The utility degree K is read exactly as in crisp ARAS: a percentage ratio against the optimal alternative, meaningful only for this alternative set and these weights, and not comparable with a different analysis.
The difference is here: beneath the score now lies a tension between support and rejection. When a judgement is given both high support and high rejection, that is, when an expert reports strong approval and a strong reservation at the same time, this duality enters the calculation but disappears from view inside K. The K gap between two alternatives should be assessed by looking not only at the weights but also at how sharp the input pairs were.
Thus instead of writing:
"According to q-Rung ARAS, A1 is the best alternative"
the report should read:
"Relative to the optimal alternative derived from this alternative set, A1 holds the highest utility degree; this ratio is meaningful only for this alternative set and these weights, and does not show on which criterion the support-rejection tension was highest"
When to Prefer This over the Base Method
Use this extension when experts give a judgement's support and rejection degrees separately, and these pairs exceed the intuitionistic and Pythagorean fuzzy boundary. It also fits when crisp ARAS's "percentage against the optimum" output is wanted under this kind of uncertainty. How q is chosen, and the boundary that must not be confused with the neighbouring types (intuitionistic, Pythagorean, Fermatean), are covered on the data-type card.
The exit condition is the same as for crisp ARAS. The matrix must be of a single type throughout, and if no compromise is acceptable on one criterion, this extension remains compensatory too.
Mistakes Specific to This Extension
Choosing q large without looking at the data. As q grows, the accepted pairs widen but discrimination falls; q should be the smallest exponent covering the whole of the expert pairs, chosen once for the entire matrix, not cell by cell.
Computing ν as 1 − μ. In that case the sum is always exactly 1, and there is no need for the q-Rung structure at all; the rejection degree must come from its own separate body of evidence.
Deriving the optimal alternative incorrectly. If the optimal row is built for a cost criterion before the pair is inverted, the best pair is picked in the wrong direction, and every K value is distorted in the same way.
Reading K as a probability. K is only a proportional measure of benefit relative to this alternative set's optimal alternative; it is not a "percentage chance of being the right choice."
The governing principle is this:
The utility degree depends on the optimal alternative derived from the alternative set, on the weights supplied, and on the support-rejection pairs that q covers; change any one of these and K changes too, and the report must show this.
Cases
The first case is DecisionMind's validation example; it is not a page carried over from the literature but was verified by running the engine itself. The second case is an illustrative construction.
1. Illustrative example: q-Rung orthopair assessment of three suppliers on three criteria
Three suppliers are assessed on three criteria with support-rejection pairs valid under q = 3. All three are "higher is better" criteria; the suppliers follow a pattern that weakens steadily across the criteria.
| Supplier | Criterion 1 | Criterion 2 | Criterion 3 |
|---|---|---|---|
| A1 | (0.90; 0.20) | (0.85; 0.30) | (0.80; 0.40) |
| A2 | (0.70; 0.40) | (0.65; 0.50) | (0.60; 0.55) |
| A3 | (0.50; 0.55) | (0.45; 0.60) | (0.40; 0.65) |
| Direction | higher is better | higher is better | higher is better |
| Weight | 0.40 | 0.35 | 0.25 |
The method builds an optimal supplier from the highest support and lowest rejection pair on each criterion (here this pair is exactly A1's own scores), reduces every row to a single pair with the q-Rung aggregation rule, converts this pair into a score between 0 and 1, and divides each real supplier's score by the optimal's score.
| Supplier | Utility degree (K) | Rank |
|---|---|---|
| A1 | 1.000 | 1 |
| A2 | 0.730 | 2 |
| A3 | 0.549 | 3 |
The result reads as follows. A1 holds both the highest support and the lowest rejection pair on every criterion, so it is the optimal alternative itself and takes K=1.000. A2 and A3 trail A1 on all three criteria; their K values reflect the weighted total of this gap.
The suppliers' order does not break down criterion by criterion in this table, so it does not reverse easily with the weights. Even if Criterion 1's weight is pulled from 0.40 to 0.25 and Criterion 3's raised from 0.25 to 0.40 (recomputed independently in Python), A2's K value only drops from 0.730 to 0.727, and A3's from 0.549 to 0.547; the ranking stays A1 > A2 > A3. The reason is that A1 is simultaneously best on more than one criterion at once, so wherever the weight shifts, A1's optimal position does not change. Weight determines the ranking when alternatives swap superiority criterion by criterion; because they do not do so here, the ranking is robust.
In the report: "With the weights given, A1 is the optimal alternative itself, since it holds the best pair on every criterion (K=1.000); A2 comes second (K=0.730), A3 third (K=0.549). Redistributing the weights across the criteria does not change this ranking, because A1 trails on no criterion."
Source: DecisionMind's QR-ARAS validation example; a synthetic table constructed so that A1 carries the best pair on every criterion, not a table from Mishra and Rani's (2023) paper. The utility degrees and the weight-change scenario were obtained by running DecisionMind's QR-ARAS engine independently.
2. Healthcare: Choosing among three imaging-device quotations
A hospital will choose among three manufacturers' quotations for a new imaging device. Three criteria are set: image quality, the device's long-term maintenance reliability, and how easily the technical team can adapt to it. For every criterion the evaluation board gave a support and a rejection degree to the judgement "this quotation is suitable for the hospital"; for some quotations the board reported both strong technical superiority and a serious service risk, so the pairs exceeded the Pythagorean boundary and were recorded with q = 3. The board gave maintenance reliability the highest weight.
The method compares the three quotations: it computes every real quotation's utility degree against the optimal quotation built from the best pair on each criterion. Suppose the quotation with the highest maintenance reliability also came out strong on ease of adaptation and finished first on utility degree; the quotation with higher image quality but weak maintenance reliability came second.
The board's hesitation: the high support-rejection pair the board gave on maintenance reliability may stem from the manufacturer's local service network not yet being tested in the field. If the first quotation's advantage rests largely on this strong but tense score, the hospital should not approve the purchase without a binding contractual service-response clause.
In the report: "With the highest weight given to maintenance reliability, the first quotation reaches the highest utility degree; because the support-rejection tension on this criterion is high, a binding contractual service-response clause is recommended."
3. What Not to Do
In the illustrative example, feeding crisp ARAS with only the support value (0.90) of an expert's (0.90; 0.20) pair, ignoring the rejection degree, is wrong; this entirely erases the reservation the expert reported. The second error is skipping the inversion for a cost criterion and building the optimal alternative directly from the observed highest support pair; this builds the optimal alternative in the wrong direction for a "lower is better" criterion and distorts every K value. The third error is reading A1's K=1.000 as "a flawless supplier"; it only means that, among these three alternatives, A1 is the optimal alternative itself.
Sources
For the formulas behind each step, the intermediate tables and citation formats, see the DecisionMind method page: decisionmind.app/library/qr-aras
Mishra, A. R., & Rani, P. (2023). A q-rung orthopair fuzzy ARAS method based on entropy and discrimination measures: an application of sustainable recycling partner selection. Journal of Ambient Intelligence and Humanized Computing, 14(6), 6897–6918. DOI: 10.1007/s12652-021-03549-3
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
Zavadskas, E. K., & Turskis, Z. (2010). A new additive ratio assessment (ARAS) method in multicriteria decision-making. Technological and Economic Development of Economy, 16(2), 159–172. DOI: 10.3846/tede.2010.10