Background
PJM Economics was commissioned (in partnership with DJS) by Severn Trent Water and United Utilities to conduct a programme of quantitative research to explore customer views on issues relating to the companies' water resources management plans (WRMP) in line with the Water Resources Planning Guidelines and the UKWIR Best Value Planning Guidelines. Key objectives included a need to assess customer preferences between supply-demand options and the metrics selected by Water Resources West to support the development of a best value WRMP for the region.
Approach
Two stated preference choice exercises were conducted in order to address the research objectives:
- A pairwise choice experiment focussed on measuring customers’ decision weights with respect to the metrics entering the Water Resources West multi-criteria tool, ValueStream.
- A ranking exercise focussed on measuring customers’ priorities for relevant water supply-demand options.
The majority of interviews within the quantitative phase, were conducted online, including household, business and vulnerable customers. The online interviews were supplemented with face-to-face interviews to ensure coverage amongst the hard-to-reach, vulnerable and digitally disengaged customers. The data were weighted to be representative of the profile of each company's customer base.
The analysis of the pairwise choice data was based on a joint econometric model combining households and businesses from all three companies to obtain more precise estimates, while allowing for differences across companies.
Results
Preference weights for the decision metrics based on the results of the pairwise SP choice experiment were derived and presented alongside weights derived prior to this study via a WRW stakeholder workshop.
Customer preference weights for Carbon emissions, Flood risk, Ecosystem resilience, and Multi-abstractor benefits were higher than the range obtained from the stakeholder workshops, while the preference weight for Human & social wellbeing fell within that range.
Additionally, the outcomes of the water-supply-options ranking exercise revealed that the preference rankings of household and business customers were very similar. The top three preferred water supply options were: increasing the size of existing reservoirs, maximising the outputs of current water treatment assets, and increasing the capacity of water treatment works.
There were several indications of validity and reliability of results, and the results were consequently recommended for use as part of the development of each company's WRMP.