Application Of Multi-criteria Decision Analysis Research Articles

Sustainability Assessment Methods for the Transport Sector Considering the Life Cycle Concept—A Review

This paper presents a summary and review of life cycle sustainability assessment (LCSA) methods for the transport sector. The paper provides a comprehensive overview of articles that employ a variety of methods for assessing sustainable development in the transport sector, taking into account the economic, social, and environmental dimensions. In the sustainability assessment of transport, three methods were evaluated: life cycle assessment (LCA), life cycle cost analysis (LCC), and social life cycle assessment (SLCA). An overview of sustainability assessment methods in transport and a review of the indicators used in the life cycle sustainability assessment was conducted. It was found that the selection of indicators within the LCSA for assessing various aspects of sustainable development is dependent on various geographic and policy contexts. An overview of the application of multi-criteria decision analysis (MCDA) methods to assess LCSA in the transport sector was performed. MCDA methods are used to support decision-making regarding the selection of the most sustainable transport options and allow for the simultaneous consideration of multiple criteria, enabling a more sustainable assessment of different transport options. MCDA methods help to rank alternative transportation fuels and help decision-makers consider indicators encompassing economic, environmental and social aspects.

Development of a Prioritization Framework to Aid Healthcare Funding Decision Making in Health Technology Assessment in Australia: Application of Multicriteria Decision Analysis

ObjectivesThis study develops a prioritization framework to aid healthcare funding decision making in health technology assessment (HTA) in Australia using a multiple criteria decision analysis (MCDA) approach. MethodsMCDA frameworks for HTAs were reviewed through literature survey to identify the initial criteria and levels within each criterion. Key stakeholders and experts were consulted to confirm these criteria and levels. A conjoint analysis using 1000Minds was undertaken with policy makers from the Department of Health to establish ranking criteria and weighting scores. Monte Carlo simulations were used to examine the sensitivity of findings to factors affecting the ranking and weighting scores. The MCDA was then applied to 6 examples of chronic care models or technologies projects to demonstrate the performance of this approach. ResultsFive criteria (clinical efficacy/effectiveness, safety and tolerability, severity of the condition, quality/uncertainty, and direct impact on healthcare costs) were consistently ranked highest by healthcare decision makers. Among the criteria, patient-level health outcomes were considered the most important, followed by social and ethical values. The analyses were robust to inform the uncertainty in the parameter. ConclusionsThis study has developed an MCDA tool that effectively integrates key priorities for HTA reviews, reflecting the values and preferences of healthcare stakeholders in Australia. Although this tool aims to align the assessment process more closely with health benefits, it also highlights the importance of considering other criteria.

The application of multi-criteria decision analysis in evaluating the value of drug-oriented intervention: a literature review.

Objectives: Multi-Criteria Decision Analysis (MCDA) has gained increasing attention in supporting drug risk-benefit assessment, pricing and reimbursement, as well as optimization of clinical interventions. The objective of this study was to systematically collect and categorize evaluation criteria and techniques of weighting and scoring of MCDA for drug value assessment. Methods: A systematic review of the literature was conducted across seven databases to identify articles utilizing the MCDA frameworks for the evaluation of drug value. Evaluation criteria mentioned in the included studies were extracted and assigned to 5 dimensions including clinical, economic, innovative, societal and humanistic value. A descriptive statistical analysis was performed on the identified drug value evaluation criteria, as well as the weighting and scoring techniques employed. The more a criterion or technique were mentioned in articles, the more important we consider it. Results: Out of the 82 articles included, 111 unique criteria were identified to evaluate the value of drug. Among the 56 unique criteria (448 times) used to measure clinical value, the most frequently mentioned were "comparative safety/tolerability" (58 times), "comparative effectiveness/efficacy" (56 times), "comparative patient-perceived health/patient reported outcomes" (37 times), "disease severity" (34 times), and "unmet needs" (25 times). Regarding economic value measurement, out of the 20 unique criteria (124 times), the most frequently utilized criteria were "cost of intervention" (17 times), "comparative other medical costs" (16 times), and "comparative non-medical costs" (18 times). Out of the 10 criteria (18 times) for assessing innovative value, "a novel pharmacological mechanism" was the most frequently mentioned criterion (5 times). Among the 22 criteria (73 times) used to measure societal value, "system capacity and appropriate use of intervention" was the most frequently cited criterion (14 times). Out of the 3 criteria (15 times) utilized to measure humanistic value, "political/historical/cultural context" was the most frequently mentioned criterion (9 times). Furthermore, 11 scoring and 11 weighting techniques were found from various MCDA frameworks. "Swing weighting" and "a direct rating scale" were the most frequently used techniques in included articles. Conclusion: This study comprehensively presented the current evaluation dimensions, criteria, and techniques for scoring and weighting in drug-oriented MCDA articles. By highlighting the frequently cited evaluation criteria and techniques for scoring and weighting, this analysis will provide a foundation to reasonably select appropriate evaluation criteria and technique in constructing the MCDA framework that aligns with research objectives.

Application of Multi-Criteria Decision Analysis (MCDA) to Prioritize Real-World Evidence Studies for Health Technology Management: Outcomes and Lessons Learned by the Canadian Real-World Evidence for Value of Cancer Drugs (CanREValue) Collaboration.

Multi-criteria decision analysis (MCDA) is a value assessment tool designed to help support complex decision-making by incorporating multiple factors and perspectives in a transparent, structured approach. We developed an MCDA rating tool, consisting of seven criteria evaluating the importance and feasibility of conducting potential real-world evidence (RWE) studies aimed at addressing uncertainties stemming from initial cancer drug funding recommendations. In collaboration with the Canadian Agency for Drugs and Technologies in Health's Provincial Advisory Group, a validation exercise was conducted to further evaluate the application of the rating tool using RWE proposals varying in complexity. Through this exercise, we aimed to gain insight into consensus building and deliberation processes and to identify efficiencies in the application of the rating tool. An experienced facilitator led a multidisciplinary committee, consisting of 11 Canadian experts, through consensus building, deliberation, and prioritization. A total of nine RWE proposals were evaluated and prioritized as low (n = 4), medium (n = 3), or high (n = 2) priority. Through an iterative process, efficiencies and recommendations to improve the rating tool and associated procedures were identified. The refined MCDA rating tool can help decision-makers prioritize important and feasible RWE studies for research and can enable the use of RWE for the life-cycle evaluation of cancer drugs.

Application of multicriteria decision analysis to assess the greenness of molecularly imprinted polymers synthesis components

The study applies multicriteria decision analysis (MCDA) to rank the components of molecularly imprinted polymers (MIPs) synthesis according to their greenness. The components are taken from papers that are describing synthesis of MIPs for persistent organic pollutants (POPs) sorbents. Functional monomers (n = 14), target/surrogate molecules (n = 10), porogens (n = 8), cross-linking agents (n = 8) and initiators (n = 4) are described with 10 criteria referring to their safety of application, toxicity, environmental persistence and bioaccumulability. The rankings are performed according to three scenarios, with the application of different weights. The ranking results give a specific guide on the selection of green synthesis components for polybrominated biphenyl ethers (PBDEs) as representatives of POPs, by identification of problematic and recommended chemicals. The results are useful in designing MIP synthesis protocols.

The application of multi-criteria decision analysis in gaining a premier sort of stability in airplane safety

Improving the aeronautical safety has been of high importance for the experts. Different factors influence the static and dynamic stability of the plane. These factors play important roles in the plane safety. The static and dynamic safety include several factors. Taking all the technical criteria and elements into account, this article tries to find a suitable method for evaluating and eventually deciding on the best alternative. One of the methods of multi-criteria decision analysis is the concordance analysis (CA) which is an important way of evaluation in solving issues of different miscellaneous criteria that cannot be incorporated into one another. Also, Best-worst method (BWM), one of the most practical decision-making methods, is used in this article. Using the CA and BWMs and based on different criteria, this research prioritises the premier stability alternatives and uses them in the design and finally suggests a suitable alternative out of the influential linear and lateral ones. To do this, a combination of extant varieties including 15 criteria and three alternatives is used and the concordance and non-concordance collections and criteria are defined. The results showed that in addition to the fact that the use of both methods led to the same results; as a result, the linear, lateral and directional became the best options for aeroplane safety, respectively, for design purposes.

Bibliometric Study on Multicriteria Decision Analysis (MCDA) Applied to the Selection of Operational Means in a Military Environment

Complex environments, conflicting criteria, uncertainties, and inaccurate information are common in many real-world decision problems. The Multicriteria Decision Analysis (MCDA) methodology plays a significant role in making decision-making processes more rational, efficient, and effective. In the military sphere, the Armed Forces of several countries have used MCDA methods to select operational means—means of transportation—that the Armed Forces have to carry out operations on the battlefield or in various operational scenarios, contributing to a more robust and informed approach to decision-making. This article aims to present a review of the literature on the main applications of MCDA in the selection of operative means. The methodology includes a bibliometric study and a bibliographic review of documents from the Scopus and Web of Science databases. The bibliometric study identified the types of documents, year of publication, H and G indexes of the most relevant journals and authors, authors’ publications, affiliation, clusters of keywords, area of knowledge, country, and main applications of the MCDA Methods in this area of research. Through this methodology, it was possible to identify that the Analytic Hierarchy Process (AHP) is the most applied MCDA method in the research area.

Integrating multi-criteria decision analysis (MCDA) with kriging and entropy methods for optimising streamflow measurement in a scantly monitored river basin

ABSTRACT Streamflow data is one of the most important inputs for the management of water resources in river basins. In this study, a GIS-based multi-criteria decision analysis (MCDA) was integrated with kriging and entropy methods for optimising a streamflow monitoring network in the upper Tekeze River basin, north-western Ethiopia. An initial evaluation based on the WMO (2008) guideline showed that the density of existing streamflow monitoring network for the upper Tekeze River basin was inadequate. Hence, 41 new streamflow monitoring stations were needed. The most important criteria for identifying suitable streamflow monitoring sites in the upper Tekeze River basin were stream order, accessibility (distance to roads), slope gradient, land use/cover and soil texture. The required number of new streamflow monitoring stations for the upper Tekeze River basin was reduced from 41 to 33 after an optimisation using ordinary kriging and entropy. The optimal number of monitoring stations for the upper Tekeze River basin including the existing ones was therefore 47. An integrated application of MCDA, kriging and entropy methods aids to optimise the location and number of streamflow monitoring stations in a catchment. The use of optimisation techniques for designing streamflow monitoring network is essential for collecting adequate streamflow data in scantly monitored basins.

Optimized landfill site selection for municipal solid waste by integrating GIS and multicriteria decision analysis (MCDA) technique, Hossana town, southern Ethiopia

Improper solid waste disposal has remained the major bottleneck for the socio-economic development particularly in urban and peri-urban areas of Ethiopia. This study was conducted with the prime aim of identifying an optimum municipal solid waste (MSW) management option subsequently selecting the best landfill site in Hossana town using integrated geographical information systems (GIS) and multicriteria decision analysis (MCDA) techniques. Accordingly, GIS integrated with MCDA was used to analyze the relative weight of each criterion and the overall suitability map where ten criteria were considered within their respective constraints. To create a landfill suitability index, environmental and socioeconomic factors such as distance from settlement, land use and land cover, lineament, slope, road, and wind direction/aspect were weighted. Population growth, waste generation rate, and waste volume/year were used to calculate the required landfill size. The study finding revealed that the town's MSW generation rate was 0.45 kg/cap/day, which was within the range of most of Ethiopian urban areas. On the other hand, the total daily and annual MSW generation was found to be 79.58 and 29,047 tonnes, respectively. Moreover, the study's findings revealed that 20.8 % of the solid waste was found was recyclable and the remaining 79.20 % was non-recyclable. Considering the future trend of waste generation, 19 ha of land in the city's Northern and Southern outskirts was chosen as a candidate landfill site with all the necessary suitability analysis. Therefore, optimized landfill site selection and better management system of MSW in urban and peri-urban areas could be achieved by the conjunctive application of MCDA and GIS.

Monitoring the Performance of Sustainable Development Goals in the Italian Regions

The Sustainable Development Goals (SDGs) are a shared agenda among countries but also a rallying point for forward-looking policy dialogue. Analysis and monitoring of the SDGs are decisive steps in evaluating possible corrective actions. This paper aims to reach two research objectives: (i) providing methodological insights for the application of multicriteria decision analysis (MCDA) in the evaluation of the SDGs and (ii) emphasizing the relevance of monitoring the outcomes of the SDGs by evaluating the Italian regions. For the first objective, an online survey among twenty academics is used, while for the second, an MCDA is proposed that compares the temporal performance of a sustainability score for each Italian region. The results, based on 27 targets, show that in 2021 the northern regions showed better performance, with the province of Trento topping the list. This is followed by Valle d’Aosta and the province of Bolzano, confirming the trio that emerged in the previous year. A very interesting fact is the growth of the central regions, which overall tend to reach a value close to that of the northern regions. In particular, Toscana, Marche and Lazio stand out for a good performance. It is also confirmed that the southern regions occupy the last places in the ranking with the only exception of Abruzzo. The implications of this paper suggest collaboration between different regions in order to achieve a social community in which resources and skills can be enhanced.

Risk mapping for Taenia solium: Applying multicriteria decision analysis in Lao PDR.

Taenia solium is ranked the most significant global foodborne parasite and the leading cause of epilepsy in low and middle-income countries. Diagnostic challenges have hampered disease control efforts to date and WHO has called for the development of risk mapping tools to assist endemic countries. This study describes the application of multicriteria decision analysis to map the risk of T. solium in Lao PDR and acts as a case study for other endemic countries. Multicriteria decision analysis was completed using census data on relevant risk factors in Lao PDR. Factors were weighted using an analytical hierarchy process. Village risk scores were calculated using a weighted linear combination and categorised using the Fisher-Jenks algorithm into low, medium, and high risk. District risk scores and categories were calculated using the mean village risk score for a district. Sensitivity analysis was completed by doubling and halving risk factor weights, one at a time, and assessing the standard deviation of scores and categories across all scenarios. A total of 2017 (23.7%) villages were classified as high risk, with 3312 (39.0%) medium and 3170 (37.3%) low risk. This resulted in 21 (14.2%) high-risk districts, 83 (56.1%) medium and 44 (29.7%) low-risk districts. The risk maps highlight two areas of interest which are high risk and low variation. The first is the northern province of Phongsaly, which is consistent with literature and anecdotal reports. The second is the southern Salavan and Xekong provinces, which have yet to be investigated in detail. Multicriteria decision analysis has provided a simple, rapid, and flexible approach to mapping the risk of T. solium in Lao PDR. The nature of the method means that it can be completed in any endemic country with available and appropriate risk factor data.

Assessment of the challenges to renewable energy technologies adoption in rural areas: A Fermatean CRITIC-VIKOR approach

Adopting renewables has recently become a critical topic due to climate change, global warming, and scarcity of fossil fuels, encouraging some nations to use fossil fuels as weapons against other countries, especially the EU. Thus, the present study investigates the challenges of adopting renewable energy technologies in rural areas as they are more vulnerable to dealing with the above issues. To this end, firstly, challenges are identified through a literature review and are evaluated using Fermatean-CRITIC to determine their significance. Subsequently, a systematic literature review on the application of multicriteria decision analysis in the renewables sector is conducted, then a novel Fermatean-VIKOR is applied to rank four district government offices according to the weighted challenges. The results indicated that the most significant challenge to renewable energy technologies adoption is “public engagement” out of eight identified challenges. Also, a sensitivity analysis is conducted to evaluate the performance of the proposed Fermatean-CRITIC-VIKOR according to the weight changes.

Application of Multi-Criteria Decision Analysis to Identify Global and Local Importance Weights of Decision Criteria

One of the main challenges in the Multi-Criteria Decision Analysis (MCDA) field is how we can identify criteria weights correctly. However, some MCDA methods do not use an explicitly defined vector of criterion weights, leaving the decision-maker lacking knowledge in this area. This is the motivation for our research because, in that case, a decision-maker cannot indicate a detailed justification for the proposed results. In this paper, we focus on the problem of identifying criterion weights in multi-criteria problems. Based on the proposed Characteristic Object Method (COMET) model, we used linear regression to determine the global and local criterion weights in the given situation. The work was directed toward a practical problem, i.e., evaluating Formula One drivers’ performances in races in the 2021 season. The use of the linear regression model allowed for identifying the criterion weights. Thanks to that, the expert using the system based on the COMET method can be equipped with the missing knowledge about the significance of the criteria. The local identification allowed us to establish how small input parameter changes affect the final result. However, the local weights are still highly correlated with global weights. The proposed approach to identifying weights proved to be an effective tool that can be used to fill in the missing knowledge that the expert can use to justify the results in detail. Moreover, weights identified in that way seem to be more reliable than in the classical approach, where we know only global weights. From the research it can be concluded, that the identified global and local weights importance provide highly similar results, while the former one provides more detailed information for the expert. Furthermore, the proposed approach can be used as a support tool in the practical problem as it guarantees additional data for the decision-maker.

Selection of Exterior Wall System and MCDM Derived Decision

In the field of construction practice, decisions regarding material selection frequently come down to a choice based on tradition, i.e. recommendations based on the experience of the engineers hired by an employer as designers, contractors, or energy efficiency engineers. In the presented research, in addition to the Employer, technical individuals were involved in the decision-making process. The harmonisation of Employer opinions and those of experts were obtained through NGT technique and Delphi based method, due to the fact that different criteria for a decision could represent a field of interest of an individual participant in the process. The result was determining the criteria, their strictness, and their weighted effect. As multi-criteria decision analysis has evolved into a powerful tool that assists decision-makers in generating “a cut above” choice in resolving specific cases and overcoming certain problems in the architectural and construction industry, the use of the MCDM method EDAS+ in the research ensured an exterior wall system ranking that was not influenced by experience or marketing.
 Without intending to favour any manufacturer of building materials, the research presents eight exterior wall systems belonging to different categories of core materials, all with individual features, similarities, and differences.
 When compared to otherwise arbitrary estimates or recommendations based on experience and the most commonly used building materials, the application of multi-criteria decision analysis in the case of exterior wall system selection for a particular 1938 Belgrade building generated more relevant selection results.

Expert Consensus on the Application of Multi-criteria Decision Analysis in Clinical Comprehensive Evaluation of Orphan Drugs(2022)

Expert Consensus on the Application of Multi-criteria Decision Analysis in Clinical Comprehensive Evaluation of Orphan Drugs(2022)

Lessons Learnt from the Application of MCDA Sorting Methods to Pipe Network Rehabilitation Prioritization

Most water distribution networks were built a few decades ago, showing symptoms of deterioration. Additionally, current renewal rates are insufficient to overcome pipe networks’ continuous ageing process. The development of methodologies for assisting the definition of pipe rehabilitation, including which pipes, and when and what financial amounts to allocate to this activity, are of the utmost importance. These methodologies typically have to attend to several points of view, for which multicriteria decision analysis (MCDA) techniques may be used. The current paper demonstrates and discusses the application of two MCDA techniques—the ELECTRE TRI-C and FlowSort—to a real water distribution network. Both techniques allowed assigning every single pipe to a predefined priority category, although the ELECTRE TRI-C proved to be more effective. These approaches imply that the planning of investment needs is carried out based on individual pipes, but these approaches are not consistent with the actual rehabilitation projects. A clustering technique called affinity propagation, together with cost functions, were applied to define and quantify homogeneous rehabilitation units. Even so, the methodology did not prove to be rigorous enough for the selection of pipes to be rehabilitated. On the other hand, it proved effective to estimate annual budgets for rehabilitation.

Multicriteria Decision Analysis Addressing Marine and Terrestrial Plastic Waste Management: A Review

This paper is a systematic review of studies that used multicriteria decision analysis (MCDA) to address plastic waste management. A literature search for scientific articles in online databases (Web of Science and Scopus) enabled us to identify 20 relevant papers from 2008 to 2021, spanning case studies in three continents. These studies focus on: plastics as a resource (material), plastics as a product (reverse logistics), and plastics as a problem (pollution). Content analysis methodology was used, with the focus being on how the authors used MCDA for managing plastic waste, which has relevance for researchers and practitioners. Alternative solutions were found for the selection of disposal methods for almost all types of plastic categorized in this review. The most popular method was AHP, followed by TOPSIS, outranking methods, MAUT/MAVT and simple weighted sums, with some studies including more than one method. The choice of criteria spanned operational (mostly), but also environmental and economic aspects to evaluate the alternatives. Less frequently, one finds criteria related to social, managerial, and political aspects. The weighting of the criteria was performed mainly by consulting experts, followed by decision makers. Representatives of the affected population or other stakeholders have been consulted only on a few occasions. The authors of the studies consider their application of MCDA was successful, highlighting mainly the importance of being able to encompass different dimensions in the evaluation of the alternatives and the transparency of the process. In most cases, a winning alternative emerged clearly, which sometimes was a combination of multiple strategies. We also report other recommendations of these authors concerning marine and terrestrial plastic waste management.

BIBLIOMETRIC STUDIES ON MULTI-CRITERIA DECISION ANALYSIS (MCDA) METHODS APPLIED IN MILITARY PROBLEMS

Military issues have great relevance worldwide since they affect the security and sovereignty of nations. In this context, the application of Multicriteria Decision Analysis (MCDA) methods is important because accurate decision-making is the deciding factor for success, which can reduce expenses and increase defense capacity. This paper aims to present a literature review on the main applications of MCDA in the military area, considering the tactical, operational and strategic spheres. The methodology includes a bibliometric study and literature review of documents from the Scopus and Web of Science databases. The bibliometric study identified the document type, language, year of publication, authors, author network, author’s publications, affiliation, keyword clusters, the field of knowledge, country and the main applied MCDA methods in military problems. The literature review allows us to verify that, as well as in other areas of knowledge, the Analytic Hierarchy Process (AHP) is the most applied MCDA method in the military area.

Application of Multicriteria Decision Analysis to Determine the Value of Prophylaxis Relative to On-Demand Treatment in Hemophilia A and Emicizumab versus Replacement Therapy in the Greek Healthcare Setting.

Hemophilia A (HA) is a rare disease that is characterized by congenital underproduction or dysfunction of the endogenous coagulation factor VIII (FVIII). The aim of the present study was to determine the value of prophylaxis versus on-demand treatment strategies for moderate to severe HA (MtSHA) patients and the value of emicizumab in the prophylaxis of MtSHA in Greece, compared with short half-life (SHL) FVIII and extended half-life (EHL) FVIII through multicriteria decision analysis (MCDA). A literature review was performed to identify a set of criteria relevant to the therapeutic approaches and therapies under investigation. A performance matrix was populated by two literature reviews and meta-analyses. The criteria selected were hierarchically classified by allocating weights on a 0-100 scale. The performances of therapies were scored at the 100-point scale. The value judgments utilized for weighing and scoring were sourced via a survey among independent multidisciplinary system stakeholders. A linear additive value function was used for the calculation of total value estimates. The participants ranked 'annual number of bleedings per patient' and 'percentage of target joint bleeds' as the most important criteria, while the least important criterion was the 'annual treatment cost' for both assessments. Based on the weights elicited and the performance in each criterion, the overall value score was higher for prophylaxis treatment (58.27) compared with on-demand treatment (40.13). In the other comparison, the most valued treatment was emicizumab (77.05) followed by EHL FVIII (71.52) and SHL FVIII (19.88). According to the participants, the most important factors for managing MtSHA patients are those related to successful management of bleeding events given their contribution to improved quality of life (QoL) and reduced morbidity. This MCDA has shown that the prophylaxis strategy was perceived as a more valuable option for managing MtSHA patients when compared with the on-demand strategy. Moreover, emicizumab adds higher value and improves patient QoL compared with replacement therapy for MtSHA in Greece. Emicizumab addresses important unmet needs due to its improved efficacy and mode of administration.

Multivariate Assessment of Procedures for Molecularly Imprinted Polymer Synthesis for Pesticides Determination in Environmental and Agricultural Samples.

In the case of quantitative and qualitative analysis of pesticides in environmental and food samples, it is required to perform a sample pre-treatment process. It allows to minimalize the impact of interferences on the final results, as well as increase the recovery rate. Nowadays, apart from routinely employed sample preparation techniques such as solid-phase extraction (SPE) or solid-phase microextraction (SPME), the application of molecularly imprinted polymers (MIPs) is gaining greater popularity. It is mainly related to their physicochemical properties, sorption capacity and selectivity, thermo-mechanical resistance, as well as a wide range of polymerization techniques allowing to obtain the desired type of sorption materials, adequate to a specific type of pesticide. This paper targets to summarize the most popular and innovative strategies since 2010, associated with the MIPs synthesis and analytical procedures for pesticides determination in environmental and food samples. Application of multi-criteria decision analysis (MCDA) allows for visualization of the most beneficial analytical procedures in case of changing the priority of each step of analysis (MIPs synthesis, sample preparation process—pesticides extraction, chromatographic analysis) bearing in mind metrological and environmental issues.