How valuable are environmental health interventions? Evaluation of water and sanitation programmes in India
Objective To evaluate and quantify the economic benefits attributable to improvements
in water supply and sanitation in rural India.
Methods We combined propensity-score “pre-matching” and rich pre–post panel
data on 9500 households in 242 villages located in four geographically different districts
to estimate the economic benefits of a large-scale community demand-driven water
supply programme in Maharashtra, India. We calculated coping costs and cost of illness
by adding across several elements of coping and illness and then estimated causal
impacts using a difference-in-difference strategy on the pre-matched sample. The pre–
post design allowed us to use a difference-in-difference estimator to measure “treatment
effect” by comparing treatment and control villages during both periods. We compared
average household costs with respect to out-of-pocket medical expenses, patients' lost
income, caregiving costs, time spent on collecting water, time spent on sanitation, and
water treatment costs due to filtration, boiling, chemical use and storage.
Results Three years after programme initiation, the number of households using
piped water and private pit latrines had increased by 10% on average, but no changes
in hygiene-related behaviour had occurred. The behavioural changes observed suggest
that the average household in a programme community could save as much as 7 United
States dollars per month (or 5% of monthly household cash expenditures) in coping
costs, but would not reduce illness costs. Poorer, socially marginalized households
benefited more, in alignment with programme objectives.
Conclusion Given the renewed interest in water, sanitation and hygiene
outcomes, evaluating the economic benefits of environmental interventions by means of
causal research is important for understanding the true value of such interventions.