Understanding demand for higher quality sanitation in peri-urban Lusaka, Zambia through stated and revealed preference analysis

Matthew Quaife,Robert Aunger,Fern Terris-Prestholt,James B Tidwell

doi:10.1016/j.socscimed.2019.04.046

Matthew Quaife, Robert Aunger + Show 2 more

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https://doi.org/10.1016/j.socscimed.2019.04.046

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Abstract

Poor peri-urban sanitation is a significant public health problem, likely to become more important as the world rapidly urbanizes. However, little is known about the role of consumer demand in increasing peri-urban sanitation quality, especially for tenants using shared sanitation as only their rental choices can be observed in the market. We analyzed data on existing housing markets collected between 9 Jun and 6 Jul 2017 using the Hedonic Pricing Method (HPM) to capture the percentage of rent attributable to sanitation quality (n = 933). We also conducted discrete choice experiments (DCEs) to obtain willingness to pay (WTP) estimates for specific sanitation components (n = 1087), and explored the implications by estimating the proportion of plots for which improved sanitation quality would generate a higher return on investment for landlords than building a place for an additional tenant to live. The HPM attributed 18% of rental prices to sanitation (∼US$8.10 per month), but parameters for several components were poorly specified due to collinearity and low overall prevalence of some products. DCEs revealed that tenants were willing to pay $2.20 more rent per month for flushing toilets on plots with running water and $3.39 more per month for solid toilet doors, though they were willing to pay little for simple hole covers and had negative WTP for adding locks to doors (-$1.04). Solid doors and flushing toilets had higher rent increase to cost ratios than other ways landlords commonly invested in their plots, especially as the number of tenant households on a plot increased. DCEs yielded estimates generally consistent with and better specified than HPM and may be useful to estimate demand in other settings. Interventions leveraging landlords' profit motives could lead to significant improvements in peri-urban sanitation quality, reduced diarrheal disease transmission, and increased well-being without subsidies or infrastructure investments by government or NGOs.

Highlights

While there are clear public health and economic benefits from investment in sanitation, a deficient understanding of the role of consumer demand could reduce the effectiveness of global efforts to ensure access to sanitation for all
The final combined data set of paired landlords and tenants (n = 933 pairs from the 1085 enrolled plots) with complete data for each variable included in the model was used to estimate the implicit prices of housing components using Hedonic Pricing Method (HPM)
We have estimated tenant willingness to pay for several important aspects of peri-urban sanitation quality in our study setting

Summary

Introduction

While there are clear public health and economic benefits from investment in sanitation, a deficient understanding of the role of consumer demand could reduce the effectiveness of global efforts to ensure access to sanitation for all. The World Bank estimates the overall cost of bringing safe sanitation to all by 2030 to be $70 billion dollars per year, less than one-third of the annual losses caused, but 70% of that amount needed for urban and peri-urban areas and most of the burden falling on national governments and international donors, as little consumer contribution is anticipated for improving sanitation (Hutton and Varughese, 2016). Recent work has shown some links between sanitation and health outcomes, including diarrheal disease, there is limited granular evidence of the impact of sanitation quality beyond having an improved slab, having a sewer connection, and moving from shared to single-family toilets (Freeman et al, 2017; Wolf et al, 2014). If we view the health impact of sanitation quality through a broader conceptual lens – such as the Healthy Sanitation Framework, which goes beyond simple prevention of infection to include hygiene, accessibility, desirability, sustainability, and use as key constructs (Tidwell et al, 2018a) – there is strong evidence of sanitation quality affecting psychosocial stress and wellbeing via aspects like safety, privacy, disgust at unhygienic conditions, and interpersonal conflict due to collective action failure (Shiras et al, 2018)

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