4.1 Overview
During the COVID-19 pandemic, emergency decision making and risk assessment have become important issues for guaranteeing the stable life of the people. However, the decision-making process often contains qualitative and quantitative information, as well as limited time. The assessment information of the criteria simultaneously includes complete, incomplete and hesitant fuzzy linguistic information, so it is regarded as an emergency MCDM problem. In order to verify the effectiveness of the proposed method, this section gives an illustrative case of the PHEDM for COVID-19 (adapted from Ashraf and Abdullah 2020). The case of public health emergency decision making for COVID-19 was composed of seven criteria and five alternatives. The basic criteria included clinical management (CM), first-aid training (FT), technician training (TT), banning intra-city transportation (BT), global uncertainty (GU), country-level coordination and planning (CP), and monitoring (MO), as shown in Table 3. The five alternatives included risk communication (A1), blocking borders and cities (A2), medical system (A3), research needs (A4), and asking the experts (A5).
The consultant committee was comprised of five experts who provided scores for the preventive emergency criteria of COVID-19, as shown in Table 4. The importance scores of the seven evaluation criteria for the five alternatives are shown in Table 5.
Table 3
Preventive emergency criteria of COVID-19
Emergency criteria | Definition |
CM | Vaccination is a massively effective preventive method for reducing COVID-19 in many countries. It is rarely seen to have severe side effects, and it is an effective disease prevention and control measure. |
FT | Due to the rapid spread of COVID-19, representatives need to undergo relevant first aid training. |
TT | The rapid sharing of viral genetic information among countries in the world will help countries develop potential vaccines. |
BT | To prevent the virus from spreading and to protect the safety of the people, the government has taken measures to ban flights, cancel various celebrations, and maintain social distancing between people. |
GU | COVID-19 has changed people's lifestyles, affected the transportation and tourism industries, caused factory closures, delayed deliveries, and harmed international trade and economic development. |
CP | The government needs to work closely with all local administrative agencies to deal with the uncertainty of COVID-19. |
MO | Government public health experts should continuously monitor the state of COVID-19 and provide suggestions to improve the situation. |
Table 4
Pairwise comparison matrix of the preventive emergency criteria
| | CM | FT | TT | BT | GU | CP | MO |
CM | Expert1 | 1 | 1 | 1/2 | 7 | 7 | 1/2 | 6 |
Expert2 | 1 | 2 | 1/3 | 4 | 6 | 1/3 | 4-5 |
Expert3 | 1 | 1 | 1/5 | 4 | 7 | 1/4 | 5 |
Expert4 | 1 | 1 | 1/3 | 5 | 7 | * | 6 |
Expert5 | 1 | 1/2 | 1/3 | 7 | 8 | 1/3 | 6 |
FT | Expert1 | 1 | 1 | 1/2 | 8 | 7 | 1/2 | 6 |
Expert2 | 1/2 | 1 | 1/4 | 4 | 6 | 1/3 | 5 |
Expert3 | 1 | 1 | 1/4 | 4-5 | 5-6 | 1/4 | 5 |
Expert4 | 1 | 1 | 1/3 | 5 | 7 | * | 6 |
Expert5 | 2 | 1 | 1/2 | 7 | 6 | 1/2 | 5 |
TT | Expert1 | 2 | 2 | 1 | 7 | 4 | 2 | 6 |
Expert2 | 3 | 4 | 1 | 4 | 5-6 | 1 | 6 |
Expert3 | 5 | 4 | 1 | 5 | 6 | 1 | 7 |
Expert4 | 3 | 3 | 1 | 4 | 7 | * | 5 |
Expert5 | 3 | 2 | 1 | 6 | 4 | 2 | 5 |
BT | Expert1 | 1/7 | 1/6 | 1/7 | 1 | 1/2 | 1/5 | 1/3 |
Expert2 | 1/4 | 1/4 | 1/4 | 1 | 2 | 1/5 | 1 |
Expert3 | 1/4 | 1/5-1/4 | 1/5 | 1 | 2 | 1/4 | 1/2 |
Expert4 | 1/5 | 1/4 | 1/4 | 1 | 3 | * | 2 |
Expert5 | 1/7 | 1/5 | 1/6 | 1 | 1/2 | 1/5 | 1/2 |
GU | Expert1 | 1/7 | 1/8 | 1/4 | 2 | 1 | 1/6 | 2 |
Expert2 | 1/6 | 1/4 | 1/6-1/5 | 1/2 | 1 | 1/6 | 2 |
Expert3 | 1/7 | 1/6-1/5 | 1/6 | 1/2 | 1 | 1/7 | 2 |
Expert4 | 1/7 | 1/5 | 1/7 | 1/3 | 1 | * | 1 |
Expert5 | 1/8 | 1/7 | 1/4 | 3 | 1 | 1/6 | 2 |
CP | Expert1 | 2 | 2 | 1/2 | 5 | 6 | 1 | 7 |
Expert2 | 3 | 3 | 1 | 5 | 6 | 1 | 7 |
Expert3 | 4 | 4 | 1 | 4 | 7 | 1 | 8 |
Expert4 | * | * | * | * | * | * | * |
Expert5 | 3 | 2 | 1/2 | 5 | 6 | 1 | 5 |
MO | Expert1 | 1/6 | 1/6 | 1/6 | 3 | 1/2 | 1/7 | 1 |
Expert2 | 1/7-1/6 | 1/5 | 1/6 | 1/2 | 1/2 | 1/7 | 1 |
Expert3 | 1/5 | 1/5 | 1/7 | 1 | 1/2 | 1/8 | 1 |
Expert4 | 1/6 | 1/6 | 1/5 | 1/2 | 1 | * | 1 |
Expert5 | 1/6 | 1/5 | 1/5 | 2 | 1/2 | 1/5 | 1 |
Note: * indicates missing/non-existent data |
Table 5
The importance of criteria for alternative of emergency public health decision
Alternative | CM | FT | TT | BT | GU | CP | MO |
A1 | 0.8 | 0.8 | 0.9 | 0.4 | 0.2 | 0.9 | 0.2 |
A2 | 0.9 | 0.4 | 0.9 | 0.8 | 0.9 | 0.6 | 0.4 |
A3 | 0.4 | 0.9 | 0.9 | 0.4 | 0.8 | 0.6 | 0.9 |
A4 | 0.1 | 0.9 | 0.8 | 0.9 | 0.3 | 0.4 | 0.7 |
A5 | 0.9 | 0.2 | 0.4 | 0.6 | 0.1 | 0.8 | 0.9 |
4.2 Application of the typical AHP method
The AHP method has the advantages of providing solutions with a multi-level and hierarchical structure, and it can systematically solve problems that contain both qualitative and quantitative elements, making it an effective tool for handling complex decisions. During information processing, the AHP method can only deal with complete information. According to Table 4, Experts 2 and 3 provided partially hesitant information, and Expert 4 provided partially incomplete information. However, the typical AHP method could only deal with complete information about the evaluation criteria for the emergency public health decisions given by the experts. Thus, only Experts 1 and 5 provided complete information that could be used to calculate the criteria weight, whereas, the information from the Expert 2-4 should be eliminated. The solution procedure was as follows:
Step 1. Calculate the criteria weights
Experts 2, 3, and 4 lacked professional knowledge of the criteria and could not give them appropriate ratings. As these limitations would lead to an invalid questionnaire, only the rating results of Experts 1 and 5 could be used to perform arithmetic average calculations for the calculation weights.
The pairwise comparison matrix shown in Table 4 was used to calculate the weight of each standard. First, the AHP method was used to calculate the arithmetic mean from Expert 1 and 5’s given scores, and then the weight calculation was implemented. The CR value was calculated to examine the consistency of the test and ensure that the judgements of the decision makers were consistent. When the CR value < 0.1 the judgements were acceptable. Eqs. (1) to (3) were used to calculate the \({\lambda }_{max}\), CI, and CR values, as shown below:
$$CI=\frac{{\lambda }_{max}-n}{n-1}=\frac{7.621-7}{7-1}=0.104$$
$$CR=\frac{CI}{RI}=\frac{0.104}{1.32}=0.078$$
Step 2. Rank the alternatives
Through the weight calculation shown in Table 4, the priority vector results indicated that TT had the most important weight value at 0.282, following by the weights of CP, FT, FT, CM, MO, and GU at 0.241, 0.189, 0.172, 0.046, 0.043, and 0.027, respectively. After multiplying the weight values of the seven evaluation criteria with the scores shown in Table 6, the weighted scores of five alternatives were obtained, as shown in Table 7. In the ranking of the alternatives, from highest to lowest, A1 was the best alternative with a score of 0.788, followed by the weights of A3, A2, A4, and A5 at 0.720, 0.708, 0.579, and 0.560, respectively.
Table 6
Computation results of the preventive emergency criteria
Evaluation Criteria | Weight | Ranking |
CM | 0.172 | 4 |
FT | 0.189 | 3 |
TT | 0.282 | 1 |
BT | 0.027 | 7 |
GU | 0.043 | 6 |
CP | 0.241 | 2 |
MO | 0.046 | 5 |
Table 7
Computation results of the emergency public health decision alternatives
Alternative | Score | Ranking |
A1 | 0.788 | 1 |
A2 | 0.708 | 3 |
A3 | 0.720 | 2 |
A4 | 0.579 | 4 |
A5 | 0.560 | 5 |
4.3 Application of the hesitant AHP method
In real life, people often provide ambiguous answers to problems due to incomplete information, and they can be severely bound by uncertainty and risk. When encountering harmful and uncertain situations, the typical AHP method can only deal with complete information. In this study, regarding the preventive emergency criteria given by the experts, as shown in Table 4, the typical AHP method would delete the partially hesitant information provided by Experts 2 and 3, causing some important information to be dismissed. However, the hesitant AHP method proposes a concept that uses a set of possible linguistic terms to represent the hesitation of the experts and uses different terms to estimate a linguistic variable instead of using single terms to solve hesitant information, and therefore it can effectively deal with the shortcomings of the typical AHP method. The solution procedure is shown as follows:
Step 1. Defuzzify the hesitant fuzzy information
According to Table 4, Expert 3 have a score to MO in CM is 4-5 which represented hesitant fuzzy information. This study used Eq. (6) and the arithmetic mean to defuzzify the hesitant fuzzy information. The average number was calculated to be 4.5 and was used in the next calculations. Other hesitant values are also used with the same method to obtain the exact value.
Step 2. Determine the evaluation criteria weight
After defuzzifying the hesitant fuzzy information, based on Table 4, Eqs. (1) to (3) were used to calculate \({\lambda }_{max}\)=7.603 and then calculate the CI value. The calculation results showed that the CR value was 0.077, which met the consistency standard (CR <0.1). The priority vector results showed that TT had the most important weight value at 0.297, followed by the weights of CP, CM, FT, GU, BT, and MO at 0.275, 0.159, 0.149, 0.044, 0.040, and 0.036, respectively.
$$CI=\frac{{\lambda }_{max}-n}{n-1}=\frac{7.603-7}{7-1}=0.101$$
$$CR=\frac{CI}{RI}=\frac{0.101}{1.32}=0.077$$
Step 3. Confirm the rankings of the criteria and alternatives
After multiplying the weight values of the seven evaluation criteria with the scores in Table 8, the weighted scores of the five alternatives could be obtained, as shown in Table 9. In the ranking of the alternatives, from highest to lowest, A1 was the best alternative with a score of 0.793, followed by the weights of A2, A3, A5, and A4 at 0.721, 0.709, 0.573, and 0.572, respectively.
Table 8
Computation results of the preventive emergency criteria
Evaluation Criteria | Weight | Ranking |
CM | 0.159 | 3 |
FT | 0.149 | 4 |
TT | 0.297 | 1 |
BT | 0.040 | 6 |
GU | 0.044 | 5 |
CP | 0.275 | 2 |
MO | 0.036 | 7 |
Table 9
Computation results of the PHEDM alternatives
Alternative | Score | Ranking |
A1 | 0.793 | 1 |
A2 | 0.721 | 2 |
A3 | 0.709 | 3 |
A4 | 0.572 | 5 |
A5 | 0.573 | 4 |
4.4 Application of the proposed method
In cases of emergencies or disasters, it is often necessary to carry out major disaster relief operations, and decision-making teams often have to be established. This requires the input of relevant experts from different backgrounds and various fields. When an emergency occurs, effective rescue methods must be provided to control and respond the emergency immediately. When asked to make a decision, experts in different fields may be unable to make quick and correct judgments or provide advice under unfamiliar situations, which usually results in nonexistent information. The traditional procedure of data collection will delete any incomplete information, which may result in biased assessment results. In order to overcome these issues, this study extended the AHP method and combined HFLTS and the soft set to solve PHEDM problems. The following steps describe the procedure:
Steps 1 and 2. Organize an emergency decision-making committee to construct and determine the emergency decision-making evaluation criteria
Gather domestic experts in various fields to form a decision-making team to respond to the epidemic, establish a structure for decision making, and define criteria or important influencing factors relevant to the decision-making as a key consideration for analyzing and judging the solutions, and ask the experts to give a score for each evaluation criteria.
Step 3. Defuzzify the hesitant fuzzy information
As shown in Table 4, Experts 2, 3, and 5 partially lacked professional knowledge of the criteria and could give them appropriate. In order to deal with the hesitant fuzzy information, the solution procedure was also completed in reference to section 4.3. According to that shown in Table 3, Expert 3 gave a score to GU in FT is 5-6, which represented hesitant fuzzy information. This study used Eq. 6 and the arithmetic mean to defuzzify the hesitant fuzzy information. The average number was calculated to 5.5 and used for further computations. The same method was then used for other information containing hesitant values to obtain the exact value.
Step 4. Fill in incomplete information
After completing the hesitant fuzzy information computation, based on Table 4, Expert 4 could not give a score to CP in CM, perhaps Expert 4 doesn’t understand the criteria mean, so the incomplete or nonexistent information has to be deleted directly in traditional data collection approach, which will lose some important information for other criteria. To overcome the challenge of incomplete or nonexistent information, this study used Eqs. (7) and (8) from section 2.3 to average the other known information and then fill in the incomplete information. The same way was used with other incomplete values to obtain the determined value and then proceed to the subsequent calculation process.
Step 5. Determine the evaluation criteria weight
The solution procedure was also completed in reference to section 4.2, after steps 3 and 4, according to Table 4, employs Eqs. (1), (2), and (3) to calculate \({\lambda }_{max}\)=7.574 and then shows the calculation for the CI value. The calculation results showed that the CR value was 0.073, which met the consistency standard (CR <0.1).
$$CI=\frac{{\lambda }_{max}-n}{n-1}=\frac{7.574-7}{7-1}=0.096$$
$$CR=\frac{CI}{RI}=\frac{0.096}{1.25}=0.073$$
After confirming the consistency of the information provided by the experts, different weight values for the weight calculations were assigned according to their degree of importance. As shown in Table 10, the priority vector results showed that TT had the most important weight value at 0.299, followed by the weights of CP, CM, FT, GU, BT, and MO at 0.275, 0.158, 0.151, 0.042, 0.040, and 0.035, respectively.
Step 6. Calculate the aggregated value of the emergency decision making and rank the alternative solutions
After finishing the weight calculations of the criteria, the results of the scores of 7 evaluation preventive emergency criteria from step 5 will multiply with 5 alternatives that are obtained in Table 11, then rank the computation result for PHEDM. In the ranking of alternatives, from highest to lowest, A1 was found to be the best alternative with a score of 0.796, followed by the weights of A2, A3, A4, and A5 at 0.720, 0.710, 0.575, and 0.573, respectively.
Step 7. Provide project team with suggestions
The results of the PHEDM ranking were used to provide the most suitable alternative anti-epidemic policy. The implementation results of the most suitable alternative were continuously reviewed to evaluate the effectiveness of the decision and confirm the problem had been solved effectively to achieve the expected goal.
Table 10
Computation results of the preventive emergency criteria
Evaluation Criteria | Weight | Ranking |
CM | 0.158 | 3 |
FT | 0.151 | 4 |
TT | 0.299 | 1 |
BT | 0.042 | 5 |
GU | 0.040 | 6 |
CP | 0.275 | 2 |
MO | 0.035 | 7 |
Table 11
Computation results of the PHEDM alternatives
Alternative | Score | Ranking |
A1 | 0.796 | 1 |
A2 | 0.720 | 2 |
A3 | 0.710 | 3 |
A4 | 0.575 | 4 |
A5 | 0.573 | 5 |
4.5 Comparison and discussion
This study used an illustrative case in Section 4.1 to compare the different computation results between the proposed method, the typical AHP method, and the hesitant AHP method. The experimental results of the three methods for the weights of the evaluation criteria and the scores for the most effective alternatives are shown in Tables 12 and 13, respectively.
Table 12
Evaluation criteria weights
Evaluation Criteria | Weight | Ranking |
Typical AHP method | Hesitant AHP method | Proposed method | Typical AHP method | Hesitant AHP method | Proposed method |
CM | 0.172 | 0.159 | 0.158 | 4 | 3 | 3 |
FT | 0.189 | 0.149 | 0.151 | 3 | 4 | 4 |
TT | 0.282 | 0.297 | 0.299 | 1 | 1 | 1 |
BT | 0.027 | 0.040 | 0.042 | 7 | 6 | 5 |
GU | 0.043 | 0.044 | 0.040 | 6 | 5 | 6 |
CP | 0.241 | 0.275 | 0.275 | 2 | 2 | 2 |
MO | 0.046 | 0.036 | 0.036 | 5 | 7 | 7 |
Table 13
Ranking of the alternatives
Alternative | Score | Ranking |
Typical AHP method | Hesitant AHP method | Proposed method | Typical AHP method | Hesitant AHP method | Proposed method |
A1 | 0.788 | 0.793 | 0.796 | 1 | 1 | 1 |
A2 | 0.708 | 0.721 | 0.721 | 3 | 2 | 2 |
A3 | 0.724 | 0.714 | 0.714 | 2 | 3 | 3 |
A4 | 0.579 | 0.572 | 0.576 | 4 | 5 | 4 |
A5 | 0.560 | 0.573 | 0.574 | 5 | 4 | 5 |
The typical AHP method can only handle exact information, moreover, the hesitant AHP method addressed only hesitant fuzzy information. If the experts provided information containing partially nonexistent information, the typical AHP method and hesitant AHP method would dismiss some available information, causing bias in the decision procedure. The proposed method was verified by numerical examples and found to be useful when encounter information containing unknown, partially known, missing, or non-existent information during the collection of COVID-19 data. The advantages of the proposed method are presented below.
First, when collecting information to solve group MCDM problems, experts in various fields such as economics, medicine, and public health may be unfamiliar or unaware of certain professional knowledge and be unable to answer certain questions, causing certain information to be unavailable. Traditionally, due to research method limitations, the typical AHP method and hesitant AHP method have been unable to handle partially nonexistent information; therefore, the typical AHP method and hesitant AHP method will often neglect important information. In order to deal with incomplete information, this study used the concept of the soft set to deal with this situation and retain crucial questionnaire information. The proposed method could calculate all possible selection values for each object and supplement missing information by means of numerical averaging to overcome the aforementioned problem of partially nonexistent information. Therefore, all the questionnaire information could be presented authentically, considered fully, and applied widely.
Second, in practice, the typical AHP method can only handle exact values; when encountering hesitant fuzzy information, the available information will be ambiguous. Therefore, questionnaires containing hesitant fuzzy information will be considered invalid and deleted, causing valuable information to go missing and easily resulting in biased assessment results. The hesitant AHP method and the proposed flexible AHP method can deal with hesitant fuzzy information by applying a defuzzification method to determine the interval value of the evaluation data set and replacing this information with the mean value. According to Table 13, after considering the hesitant fuzzy information, the A2 and A3 for ranking of alternative is2nd and3rd in the hesitant AHP method and proposed flexible AHP method, different from the typical AHP method with 3rd and 2nd, in addition, the result of typical AHP method may have significant errors in emergency medical resource allocation.
Third, based on Table 4, it contained hesitant fuzzy information (Expert 3 and 4) and partially nonexistent information (Expert 5). Due to the hesitant AHP method being unable to handle partially nonexistent information, as shown in Table 13, the calculation result of the hesitant AHP method indicated that A4 (0.572) was ranked fifth and that A5 (0.573) was ranked fourth. The closeness of these values could cause errors in ranking. However, because of the proposed flexible AHP method being able to deal with unknown, partly-known, missing, inexistent, or hesitant fuzzy linguistic data, it could fully consider the available information and distinguish small numerical differences. The calculation result showed that A4 (0.576) was ranked fourth and A5 (0.574) was ranked fifth, which was the correct ranking. This result showed that the proposed method could allow decision makers to fully consider the available information.
Table 14
Differences between the three calculation methods
Method selection | Solving characteristic |
Hesitant information | Missing or nonexistence information | Full consideration of all available information |
Typical AHP method | X | X | X |
Hesitant AHP method | O | X | X |
Proposed method | O | O | O |