Sridhar Vedachalam* writes in with some useful analysis:
David talked about the relationship between access to water and quality of governance in an earlier post,** with the hypothesis that quality of governance impacts the reach of clean water to the people in that country. I want to take that analysis a step further and find out how access to clean water and sanitation affects human development. In the broadest sense, human development is a paradigm or an environment where people can develop their full potential and lead productive and creative lives. While several factors can hinder or enhance human development, I am sure everyone will agree that access to water and sanitation is one of the important ones. Clean water and sanitation not only helps in the biological development of a person, but is also a social and economic gateway to the rest of the society.
Human development is most commonly measured using the Human Development Index issued by the United Nations. HDI consists of three independent metrics – life expectancy index (LEI), Education Index (EI) and Income Index (II). If we think about it, lack of access to water and sanitation affects each of the indices. However, the question I want to ask is which one of two factors – access to clean water, or access to sanitation – affects HDI more. In other words, can the knowledge about one of these factors tell us anything about the HDI of the country?
Let’s begin by understanding the difference between access to clean water and access to sanitation, and see why they may not measure to be the same (purely in terms of numbers). Access to clean water is determined by the percentage of population using improved water sources such as household connections, protected dug wells, public standpipes, boreholes, etc. Similarly, access to sanitation is determined by the percentage of population using improved sanitation such as connection to a public sewer, septic system, pour-flush latrine, etc.
A simple plot of access to clean water vs. access to sanitation reveals a decent fit (R2 = 0.59) and the correlation between the two variables is 0.76. While the variables are somewhat correlated, it is pretty hard to estimate the access to improved sanitation using the numbers for access to improved water. Some of egregious examples include Chad (48% and 9%), Burkina Faso (72% and 13%), Ghana (80% and 10%) and India (89% and 28%). The numbers in the parenthesis denote the percentage of people having access to improved water source and improved sanitation, respectively. Except in a few countries like Afghanistan and Papua New Guinea, there is greater access to clean water than sanitation in all the countries. This may be due to several reasons, but one of the prominent ones is that sanitation requires water, and if there’s very little of it, most of it goes for satiating thirst and cooking.
Getting back to the earlier question of which one is a better indicator of HDI – access to clean water or access to sanitation, let’s plot both these factors against HDI.
A plot of HDI Score against access to improved water source reveals an R2 of 0.65 and the correlation between the variables is 0.80.
A plot of HDI Score against access to improved sanitation reveals an R2 of 0.75 and the correlation between the variables is 0.86. It appears that access to sanitation is a better indicator of a country’s HDI as compared to access to clean water. Does that shock anybody?
In summary, sanitation requires “more” development, since it is a next step to having just access to clean water. As a result, it is a better proxy for the presence of institutions for inclusive development that ultimately result in better HDI indicators. Sanitation (and water) access is not just an economic issue in several countries, but also an institutional, cultural and social issue. Hence, low access rate also underscores lack of action on several fronts, many of which are beyond the scope of centralized planning. However, targeted investments by governments in not just institutions, but also communities and individuals will result in sustained progress. By giving attention to the water and sanitation access issue, countries can hope to start chipping away at the Millennium Development Goals (MDGs) at the same time, given that access to these two issues are closely tied to all the eight MDGs and several targets included within them.
* Sridhar Vedachalam is a PhD candidate in Environmental Science at The Ohio State University. His dissertation is on wastewater management in rural Ohio and he plans to graduate in June 2011.
**Although David had posted his raw data, I had started off with a different data source. The plots are based on 2006 data for water and sanitation access and the HDI Index released by UN in 2008 (which corresponds to 2006 information). These numbers would have changed over the last 5 years (most likely gone up), but I don’t expect the central premise to change drastically in such a short span even if a few countries have made tremendous progress in any of the indices we discussed above. Raw data available here [xls].