Development of a water quality index model: a comparative analysis of various weighting methods

Md Galal Uddin, Agnieszka I. Olbert, Stephen Nash, Azizur Rahman

Research output: Book chapter/Published conference paperConference paperpeer-review


The Water Quality Index (WQI) model is a popular tool for the assessment of water quality (WQ) and its status classification. Over the last 50 years, many different WQI models have been developed; while the four-component structure remains common across the models, they vary in approaches in terms of parameter selection and their associated weightings, and the methods used for sub-indexing and aggregation. In this research, the parameter weight factors are investigated. The parameters are assigned weightings depending on their significance to the assessment. Recent research has revealed that that the WQI models generate a significant amount of uncertainty as a result of this process. Most of the WQI models widely used the expert opinion or analytical hierarchy process (AHP) to estimate the parameters’ weight values. Many researchers have argued that these methods do not accurately represent the importance of parameters. The aim of this study is to compare various statistical weighting approaches and propose the most accurate method for calculating weight values in terms of uncertainty. To estimate the weight value of parameters, four statistical attribute weighting methods were used: (i) rank sum (RS), (ii) rank reciprocal (RR), (iii) rank order centroid (ROC), and (iv) equivalent (EQ). In this study, the Guide to the Expression of Measurement Uncertainty (GUM) approach was used to quantify uncertainty of the weighting process by implementing Monte Carlo simulation (MCS) technique. The finding of this study shows that the ROC method pro35 duces the highest uncertainty, while the RS and EQ methods generate relatively lower uncertainties. In terms of uncertainty, the results suggest that the rank sum method is an effective method to estimate the weight value in developing a WQI model.
Original languageEnglish
Title of host publicationDevelopment of a water quality index model - a comparative analysis of various weighting methods
Number of pages6
Publication statusPublished - 2024
EventMediterranean Geosciences Union Annual Meeting: MedGU-21 - Istanbul Technical University, Instanbul, Turkey
Duration: 25 Nov 202128 Nov 2021

Publication series

NameMediterranean Geosciences Union Annual Meeting (MedGU-21). Istanbul. 2022


OtherMediterranean Geosciences Union Annual Meeting
Internet address


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