# 199

Dear Morteza Yazdani, Chenchui Ye , Mayssam Tarighi Shaayesteh , Pascale Zaraté

I read your paper:

International Journal of Production Management and Engineering Decision making model for waste management: fuzzy group AHP-CoCoSo

My comments

1- You say “Through our proposed method, decision-makers’ weights and criteria weights are calculated, while fuzzy CoCoSo is utilized to determine the final collective decision ranking”

I don’t think that you can call “calculation” when the weights come from intuition, let alone use fuzzy, which simply will find a average value of invented weights that are not related to reality, but to the moods of the DM. If you use several experts, the uncertainty most probably will decrease but that procedure demands the work of many experts, as many as different criteria, and then, a comparison between say criterion health with criterion SOx emission, where non of the two experts, a MD and an environmentalist, is proficient on the field of the other. Therefore. How can they reach an agreement?

2- Page 3 “Several factors need to be considered when selecting a suitable location, including waste supply, transportation costs, environmental impact, and resource efficiency.”

I do not think that 4 criteria are enough to evaluate sites; a real-life work performed by Laura Tasca (2006) in Italy, used 11 criteria. Without too much analysis it comes to my mind aspects as: People consultation, production of noxious gases from the installation, noise due to constant trucks traffic, odors, devaluation of properties close to the site and along the tracks routes, prevailing winds, force of winds, humidity, elevation, stacks height, investment and working capital, amortization, cash flow , number of furnaces, impact on wildlife, land use, transmission lines, legal aspects, peroneal recruitment, imperialization of soil for garbage store, leach treatment, etc.

3- Page 3 “The focus is on creating a robust approachthat addresses the complexities inherent in selecting optimal waste disposal sites through a group decision-making process”

A robust approach using AHP? I doubt it.

In this type of projects most criteria are directly or indirectly related, however, you know that AHP only works with independent criteria, consequently, by using AHP you are violating the structure of the method, as Saaty clearly stated, aggravated by upplying fuzzy, something that Saaty said shouldn’t be done because the method is itself fuzzy. I would like to know the explanation for these violations.

4- Page f4 “Initially developed to address the decision-making needs of the United States military, AHP has evolved into a fundamental algorithm employed across diverse domains.”

This is true, regrading the Army influence, but utopian that it evolved into a fundamental algorithm. It was designed following the centuries old hierarchy model from top to bottom, that was followed by most companies up to mid of 20th Century. For this reason, AHP was the ideal and valuable tool, but that changed when companies changed their structures and adopted the network structure. From them on, AHP was no longer useful for them especially after the creation of ELECTRE, PROMETHEE, TOPSIS, VIKOR and many others. This is something that I have asked many times regarding why AHP continued to be used, and along 10 years in RG nobody rebutted and illustrated me. Strange, indeed!

Most probably Saaty should have recognized this change, and created ANP, based on a network. Very suggestive!

5- Page 4 “Subjectivity in choosing a singular numerical representation of the perceived importance of relationships between two criteria becomes a stumbling block”

Very true, but do not forget that the Fundamental Table is the result of using the Weber-Fechter psychology law that related incentiveswith results in a log dependency. AHP uses the same law but with the difference that weights are not incentives, that denote a progress, a reward, while weights are only a ratio between two invented estimates. This is another false attempt to adapt this law to a different concept than incentives.

6- “The amalgamation of fuzzy theory with AHP introduces a more nuanced approach”

Well, it is your opinion, but remember that in so doing, when you use the Eigen Value approach, this system does not accept fuzzed values, because there could not be a guaranty of transitivity thar VA demands.

7- Page 8 “C5: The proximity to the urban and city infrastructure (society) (benefit)”

I fail to understand how this can be considered a benefit, for me it is the opposite. From the society point of view, the farthest the waste furnaces from the urban area, the better

8- “However, due to the inherent complexity arising from the interplay of eight criteria, decision makers may encounter instances where the Consistency Ratio surpasses the acceptable threshold of 0.1. In response to such occurrences of inconsistency, the decision support system initiates corrective measures by prompting decision makers to revise their inputs”

In other words, who decides is a system, not a human being, and if the DM refuses to modify a former appreciation, the system does not allow to go further. This is a ‘robust’ method. Where is the logic?

And going to the root, why the DM must be consistent in his estimates? It is axiomatically true that if A>BC, yes, in mathematics, but not on the way we humans think, not precisely in mathematical ways, and also considering many other aspects like mood, fatigue, not understanding the question, uncertainty, indecision, etc. Fortunately, we are more complex than an axiom.

9- Page 9 “This iterative process continues until the achieved Consistency Ratio aligns with the predetermined threshold”

What does this mean? What threshold are you talking about?

By the way, this is not an iterative process, because each successive step is not based on a former.

“Once all ten decision makers have completed inputting their preferences and achieved Consistency Ratios below 0.1”

I would say that the correct expression is ‘and forced to achieve”

These are my comments, hoping they can be of help

Nolberto Munier