A new paper published in Nature Water this week by Ian Ross and colleagues from LSHTM, and around the world, uses rigorous psychometric methods to validate an index of Sanitation-related Quality of Life (SanQoL-5) in six countries in Africa and Asia. Ian explains why this matters.

What’s the issue?

Globally, 1.5 billion people currently lack access to a basic toilet, which spreads disease. To assess progress on sanitation, the UN measures the types of toilets people use – this is measured by their Sustainable Development Goal 6.2. Improving people’s subjective sanitation experiences is also important, but these broader quality of life outcomes are rarely rigorously measured.

What do you mean by “quality of life”?

Amartya Sen’s capability approach to welfare economics frames quality of life as whether people can be and do the things in life they value. Sanitation-related quality of life is a subset of overall quality of life and what people value the most about sanitation such as their subjective level of privacy, safety, or disgust while using toilets.

Why is measuring quality of life important? Shouldn’t we just focus on disease?

Measuring quality of life outcomes is important because they are often rated highly (and alongside or above disease) as drivers of household sanitation decisions.  If we can find ways of promoting sanitation which improve quality of life to the greatest extent, more people will gain access to sanitation more quickly. These outcomes also contribute to health in its broadest sense via mental wellbeing. In our earlier qualitative study, people said “I'm afraid to use [the toilet] at night because of falling into the hole”, and “when a toilet is not secure you do not feel free to use it because at any moment an individual can enter.”

So where does this new paper come in?

A few years ago, our team developed the Sanitation-related Quality of Life index (SanQoL-5) in urban Mozambique. It combines answers to five simple questions (disgust, privacy, disease risk, shame, safety) into an overall score ranging 0.0-1.0 which can be used to evaluate interventions. In the paper that we published this week, we extended that to the rural and urban areas of five countries, assessing SanQoL-5 in Ethiopia, India, Kenya, Malawi, Mozambique, and Zambia. We interviewed over 6,000 people to check whether SanQoL-5 is a valid and reliable tool for evaluation.

What did you find?

Our results show that sanitation implementers and researchers can use the SanQoL-5 index to monitor and evaluate sanitation programmes. We found support for 87% of hypotheses we tested about how SanQoL-5 scores would vary with toilet characteristics such as locks on doors, quality of walls, or faeces being visible. We also found good evidence of cross-cultural comparability, with <10% of inter-country comparisons suggesting questions were being interpreted differently. We had great collaborators across the 6 countries to make this happen.

What practical purposes can the index be used for?

SanQoL-5 can be used in impact evaluation, monitoring, needs assessment, and benefit-cost analysis. Three NGOs are already using SanQoL-5 for monitoring (WSUP, World Vision, and Sanergy). Step one is assessing which kinds of approaches to promoting sanitation improve sanitation-related quality of life to the greatest extent. Step two is bringing in the cost side of the equation to identify which approaches do so most efficiently. If that information is then used to  target resources, more people would then benefit from the same budget.

What is the health economics angle on this?

First, the SanQoL-5 index is designed for economic evaluation. That means the five attributes (privacy, disgust etc.) are not weighted equally. Why? Because for a measure to be used for a cost-effectiveness or benefit-cost analysis, attributes should be weighted according to people's relative value of them. For example, if a given population thinks that avoiding disgust is more important than avoiding shame, our analysis must reflect that preference in order to be valid in economic evaluation.

We explored those weights in another study. Being designed in that way also allows us to use methods analysing the willingness to pay to put monetary values (dollars, kwacha, shillings) on improvements in SanQoL-5. Our ongoing work in Malawi is focused on that, using contingent valuation to put a price on the gains, and then including them in a benefit cost analysis of a rural sanitation intervention. Watch this space!

How will this benefit people?

If SanQoL-5 starts being used in more benefit-cost analyses, it will allow funders and implementers to identify the most efficient interventions for improving sanitation, meaning more people can benefit from a given budget. SanQoL-5 could also be used purely from an effectiveness perspective, to see which ways of promoting sanitation improve quality of life to the greatest extent.

Publication

Akter, F et al. Validity and reliability of the Sanitation-related Quality of Life index (SanQoL-5) in six countries. Nature Water (2025). http://doi.org/10.1038/s44221-025-00434-7