# 154

Dear Abolfazl Azadi · Alireza Seyed Jalali · Mir Naser Navidi

I read your article:

Land evaluation approaches comparing TOPSIS and SAW with parametric methods for rice cultivation

My comments

1- If there is something outstanding in this paper is the professionality it was written, the profusion of references and the technical content, with some exceptions.

2- In page 1 you say “Therefore, this study aimed to compare the efficiency of the parametric method (square root)”

I believe that you should explain what parametrization is because not all readers are familiar with mathematics, even those working in MCDM and with knowledge of its methods such as SAW, TOPSIS, AHP, etc.

I find your text difficult to understand, however, I guess what you have is a set of different locations that are the alternatives, and the soil characteristics of each one the criteria, which I believe is the case. That is, given a set of different locations for 28 paddy fields, that are subject to a set of characteristics or criteria, find the ranking of best locations. Am I correct? The paper does not explain it clearly even when mentions many times the criteria; it is confusing.

3. What is a land index? For people like me that are not in the agricultural activity, that expression is unknown. Of course, agronomist and scientists, do not need to be explained, but in turn, they need to be made aware of mathematical or MCDM terms since probably for them the acronyms SAW and TOPSIS and parametric, mean nothing. In these cases, I suggest to write a glossary at the beginning of the paper. This way, everybody will understand of what you are talking about.

4- Page 2 “The analytic hierarchical process (AHP) is one of the most common MCDM methods. This method, in combination with geographic information systems (GIS), is widely used to determine the relative weight of decision criteria and to assess ecological capability”

I agree that AHP is one of the common and used MCDM methods, but in my opinion, it is not adequate to solve this kind of problem. The main reason is that if the criteria are the characteristics of the paddy soil, they refer to flooded fields, with nutrients and little drainage. There are of course other characteristics as texture. If I am not mistaken, all of these characteristics, and possibly many others are interrelated. If this is right, you cannot use AHP, because it demands independent criteria. Saaty clearly said so, not me.

5. Page 2 “AHP was used to weigh the layers of information based on several biological and ecological factors”

For the same reason as in 4) AHP can not be normally used in GIS because in one way or another all the layers are normally related.

6 – “As a result, the AHP method was found to be highly accurate”

This is a common assertion practitioners say when using MCDM methods, but it is false, because to measure accuracy you have to make a comparison with a yardstick, that you do not have in none of the more than 200 MCDM methods. The fact that there may be coincidences for a same problems using different MCDM, means nothing.

7- Page 3 “found the weights of the criteria with the AHP method”

The weights found by AHP are arbitrary even if produced by experts, and in addition absurd, because you can legitimately say that criterion ’texture’ is for YOU more important than say criterion ‘drainage’, this makes sense, but what does not make any sense, if assigning a value to such preference.

8 – Page 9 “Several statistical methods have been used in this study to validate the results of the used models, including the correlation coefficient (R2 )

There is a mistake here, since R2is the coefficient of determination, that measures the ability of any statistical model to predict a result

9- Page 12 “Considering the results presented in Table 6, in terms of importance degree, based on the weights obtained from the AHP models, soil texture has the highest weight, and CCE has the lowest weight”

What guaranty offer the AHP weights? None.

I would rely more on what the experts say, but without assigning any number of preferences between two criteria, but by assigning a value say from 1 to 10 when considering each criterion independently

The paper speaks about a consistency among the expert’s values working on AHP, and this FORCED consistency by what a formula says, and correcting experts’ opinions, is absurd. Using the pair-wise comparisons and assigning arbitrary values to a preference, has been rejected by scientists since the AHP appeared. In addition, remember that the consistency achieved, only measures the coherence of the experts, but it does not mean that this can be transferred to the real world, which, in general is non-consistent. It is not supposed that somebody may ask Nature for consistency.

10- Pag 17 “The authors claimed that TOPSIS provides better prioritization capability due to its ease of use and weighting of evaluation criteria compared to conventional methods (parametric methods)”

I do not share your assertion that conventional methods are parametric. Parametric, means changing some parameters considering their subjacent probabilistic distributions, and as my knowledge, the more that 200 MCDM methods are not based in that condition when performing sensitivity analysis.

These are my comments. I hope they can help

Nolberto Munier