3.1. Definition of the Process for Analyzing the Information
One of the main drawbacks of the coefficient-of-variation formulation is that it only includes historical information, leaving out any knowledge or expectation of the immediate future that the experts and decision makers have about the topic being analyzed [
27]. Therefore, in addition to the traditional analysis, using different operators that provide new insight by aggregating different elements of information will provide a better understanding of the problem and generate new, unforeseen scenarios [
28,
29]. In agricultural production, price volatility becomes an important element to analyze because it will help the farmers decide which product to sow [
30,
31].
The following steps should be followed to obtain the variation based on the OWA operators and their extensions:
Step 1. Determine the period for calculation (e.g., quarter-year, half-year, full-year) based on decision criteria.
Step 2. Collect price data.
Step 3. Define a weighting vector reflecting the importance of the information and the decision maker’s knowledge. In this step, the values of the vector used in the OWA operator are obtained.
Step 4. Obtain the weight vector for heavy values, adjustable from −∞ to ∞, enabling under- or over-estimation of the result as needed. The main idea is to obtain weights that will correspond to the expectations of the following year’s prices. If the price is expected to rise, then the value of the vector must be higher than 1, and if the price is expected to fall, then the weights must add up to less than 1.
Step 5. Establish an ordered vector to arrange weights according to the expectations of the decision maker. The idea is to obtain induced values in which the ordered weights align to the values. The induced vector incorporates the visualization of specific situations that are not included in the original weight’s values.
Step 6. Develop a probability vector. Also, ensure that the sum of the percentages allocated to weighting and probability vectors is 100%. Probabilities will help incorporate the information considering different elements, this time using the concept of the percent of occurrence of that value. An important thing to consider in this step is that the relative importance of the weighting and probability vector is defined.
Step 7. Using information from Steps 1 to 6, construct diverse formulations using and its extensions. Consider the general formulation case 1 and case 2.
Step 8. Conduct an analysis using outcomes from various operator formulations.
3.2. Case of Rice Prices in India in 2022–2023
Step 1. We identify how often the latest data are available. The Ministry of Commerce and Industry of the Government of India provides the rice price data monthly.
Step 2. With the information provided, the average monthly spot price of the rice is obtained from April 2022 to March 2023 (see
Table 1).
Step 3. From this step onward, an expert (an advisor to the agricultural sector with more than 10 years of experience, specifically with companies that grow rice) is consulted about the weights that should be used. The idea is to obtain the expectations of the decision maker about different elements. The weighting vector is defined as follows:
W = (0.05, 0.05, 0.05, 0.05, 0.08, 0.08, 0.08, 0.10, 0.10, 0.12, 0.12, 0.12)
This vector considers the relative importance of each month to the average; that is why the expert gives a higher score to the most recent months and a lower value to the further months, because as per their experience, the future price will be more related to the newer values than the older ones.
Step 4. The heavy weights vector is defined as follows:
H = (0.05, 0.05, 0.05, 0.05, 0.10, 0.10, 0.10, 0.10, 0.15, 0.15, 0.15, 0.20)
The reason for these values is that the price is expected to increase because of the macroeconomic events still having a considerable influence on the prices of agricultural products. The expert also informs that rice prices will increase according to product demands; some news agrees with this forecast [
32].
Step 5. The induced vector is defined as follows:
U = (1, 3, 2, 6, 8, 9, 5, 4, 7, 10, 12, 11)
These values represent the expectation of the expert that the future prices will have values similar to the prices during the reference month, that is, they will fall within the highest and lowest prices of the reference month.
Step 6. A probability vector P consists of probabilities assigned to different events or outcomes, reflecting the likelihood or chance of each event occurring. The vector is defined as follows:
P = (0.05, 0.05, 0.05, 0.05, 0.05, 0.10, 0.10, 0.10, 0.10, 0.10, 0.10, 0.15)
The weighting vector carries a weightage of 60%, emphasizing its significance in the overall assessment. In comparison, the probability vector holds a weightage of 40%, contributing to evaluating the probabilities associated with different outcomes.
Step 7. With the information provided by the expert, the different results are calculated using the traditional formulation and the OWA operators and its extensions. To understand the process better, the results are explained in detail next.
3.2.1. Coefficient of Variation
The first result was obtained using the traditional formula of coefficient of variation (see
Table 2).
To calculate the standard deviation:
The coefficient of variation is = 0.14305.
Applying the traditional formula for the coefficient of variation to the provided rice price data, we obtained a mean (μ) of 915.67 and a standard deviation (σ) of 130.987. This calculation results in a coefficient of variation of approximately 0.14305, offering a quantitative measure of rice price variability essential for risk assessment and decision making.
3.2.2. Coefficient-of-Variation Calculation Using OWA Operators and Their Extensions
A specific analysis for each operator was carried out to understand how the formulations are being used. To understand the most complex situation, the general formulation is presented; this is the case where the aggregation operators are used in both and .
- (a)
operator (see
Table 3): It assigns different weighting factors to x-prices, reflecting their varying importance in the analysis. This customization allows stakeholders to tailor the analysis to their specific objectives and data characteristics. The correspondence between weighting factors and x-prices is crucial for quantifying the impact of each data point on the calculated coefficient of variation
. It offers flexibility, transparency, and sensitivity analysis to ensure robust results and informed decision making.
To calculate the standard deviation:
The is = 0.1434.
The calculated standard deviation (σ) and resulting of 0.1434, indicate the level of rice price variability, providing a key quantitative measure for risk assessment.
- (b)
operator (see
Table 4): It is effective in quantifying rice price variability, offering an alternative perspective for assessing risk. The correspondence between the weighting factors and the x-prices allows for customization, reflecting the varying importance of data points in the analysis. This flexibility makes it a valuable tool for stakeholders to tailor risk assessments and decision making to their specific objectives and data characteristics.
To calculate the standard deviation:
The is = 0.1424.
Using the IOWA formula for the coefficient of variation with the provided rice price data, we found a mean of 948.70 and a calculated standard deviation (σ) of 135.09. Therefore, the coefficient of variation is approximately 0.1424, offering a valuable quantitative measure of rice price variability, aiding in risk assessment and decision making.
- (c)
operator (see
Table 5): The correspondence between the weighting factors and the x-prices allows for a customized assessment of risk, reflecting the varying importance of data points.
To calculate the standard deviation:
The is = 0.2682.
The resulting high coefficient of variation , of 0.2682, signifies substantial price variability, making this methodology valuable for stakeholders in risk assessment and decision making, particularly in scenarios with significant data heterogeneity.
- (d)
operator (see
Table 6): It quantifies rice price variability with a unique combination of weighting factors. The correspondence between the weighting factors and the x-prices allows for tailored risk assessment, accommodating the varying importance of data points.
To calculate the standard deviation:
The is = 0.1436.
The resulting coefficient of variation of 0.1436, provides a valuable measure of price variability, offering insights for stakeholders in risk assessment and decision making in the context of this particular formulation.
- (e)
operator (see
Table 7): It is a specialized mathematical aggregation operator that allows decision makers to assign higher weights or importance to specific criteria or attributes within the decision process.
To calculate the standard deviation:
The is = 0.2623.
A higher indicates that the data have a higher level of variability relative to their mean, while a lower suggests that the data are more stable and have less variability relative to their mean.
- (f)
operator (see
Table 8): This operator allows for the customization of weighting factors based on the importance of specific criteria, combining both weighted and probabilistic considerations.
To calculate the standard deviation:
The is = 0.1422.
The result is in an value of 0.1422, signifying rice price variability. This information, complemented by the standard deviation (σ) and mean (μ), supports risk assessment and decision making. Lower values indicate price stability, while higher values imply greater variability, enabling stakeholders to align strategies with their risk preferences effectively.
All the information and the results of the coefficient of variation using the different aggregation operators and the generalized formulation (case 1 and case 2) are presented in
Table 9.
Step 8. With results obtained from
Table 9, it is possible to visualize that the coefficient of variation of the price of rice in India goes from 0.1079 to 0.3556. In a more detailed analysis, it is possible to assume that the price can vary from 10% to 36% for the following months. This interpretation is critical because a heavy-weighting vector may not provide the most accurate estimate of rice prices in India, but stakeholders still want to incorporate it into their calculations because they believe it aligns with expectations of high demand for rice in the future, which is in line with what they have seen in news reports. This decision reflects a balance between potentially biased data and market insights.
Furthermore, this examination has the potential to enable the prediction of various factors, including the projected quantity of rice cultivation. A farmer’s choice of agricultural product to cultivate hinges on their anticipation of future product prices. Presently, a product might have a certain price, but the actual harvest occurs later. Consequently, having diverse methodologies that facilitate the visualization of potential price ranges for the product becomes crucial. This insight helps ascertain whether engaging in its cultivation would be a lucrative decision.
Simultaneously, policymakers can leverage these formulations to gain enhanced foresight into the future. Through these emerging scenarios, they can develop more strategic policies and regulations to oversee the engagement of distinct economic sectors. For instance, when the visualization of price fluctuations exceeds governmental projections, a measure such as acquiring derivatives can be employed. This serves to mitigate the risk of losses within the agricultural sector.
Employing distinct formulations within the traditional coefficient-of-variation framework enhances decision-making perspectives, enabling the exploration of new scenarios inaccessible via the traditional approach. Integrating these novel operators empowers subject matter experts to incorporate decision makers’ knowledge, expectations, and attitudes, enriching the result.
The analysis results, derived from various formulations assessing rice price volatility, hold significant implications for diverse stakeholders. These findings, characterized by differing levels of price variability, play a pivotal role in shaping economic decisions and policy considerations. Stakeholders, including farmers, traders, and policymakers, can employ these insights to gauge and mitigate risks associated with price fluctuations. The comparative analysis underscores the importance of selecting the appropriate volatility measure, enabling more informed decision making. Furthermore, the results may spur further research and the identification of actionable strategies to enhance price stability in the rice market, benefiting both the agricultural sector and consumers.