Index of Drinking Water Adequacy (IDWA): International and Intra-national Exploration

6. Data on Drinking Water Access: The Case of Vietnam

Data on Drinking Water Access: The Case of Vietnam 133 133 Data on Drinking Water Access: The Case of Vietnam Ngo Quang Vinh 1. Introduction The Index of Drinking Water Adequacy (IDWA) is based on averaging five component indexes of which one key component refers to “access”. Access data are used widely in the Millennium Development Goals (MDGs) and are based on the estimates reported in the database from the Joint Monitoring Program for Water Supply and Sanitation (JMP). JMP was formulated by the World Health Organization (WHO) and the United Nations Children’s Fund (UNICEF) to monitor the progress towards the targets relating to drinking water and sanitation. The JMP’s mission is “to be the trusted source of global, regional and national data on sustainable access to safe drinking water and basic sanitation, for use by governments, donors, international organizations and civil society”. Since “access” data are critical to proper monitoring of MDGs, it is only fair and appropriate that an evaluation of the JMP database is attempted. 6 134 Index of Drinking Water Adequacy (IDWA) Taking Vietnam as a case study and data on drinking water access from the JMP as an example, this paper will briefly outline how JMP collects the data on drinking water access and then summarize a few critical points on advantages and disadvantages of the JMP methodology in general. Finally, an insight into Vietnam data are provided on the basis of analyzing the pertinent data from the JMP database as well as comparing the data on Vietnam with those of China and Thailand, which is to serve to demonstrate how much more can in fact be learnt from a wide-ranging cross-country study of JMP data and methods. 2. The Joint Monitoring Program (JMP) Data Sources and Definitions Currently JMP has a huge database of nearly 900 nationally representative household surveys and censuses from about 190 countries. JMP data sources include national censuses and surveys, Demographic and Health Surveys (DHS), Multiple Indicator Cluster Surveys (MICS), World Health Surveys (WHS) and Living Standard Measurement Surveys (LSMS).1 As definitions of “access” can vary widely within and among countries and regions, and as JMP is mandated to report at global level and across time, it must use a set of categories for “improved drinking water sources” from WHO to analyze the national data on which its trends and estimates are based. “Improved drinking water sources” under WHO category include piped water into dwelling (or house connection), piped water to yard/plot, public tap or standpipe, tube-well/borehole, protected dug-well/spring, bottled water (in some cases) and rain water collection. “Access to water” is broadly defined as the availability of at least 20 litres per person per day from a source within one kilometer of the user’s dwelling. The instructions in more recent national surveys in some countries even clearly stated that piped systems should not be considered 1 See Annex for a brief write-up on DHS, MICS, WHS and LSMS. Data on Drinking Water Access: The Case of Vietnam 135 “functioning” unless they were operating at over 50% capacity on a daily basis and that hand-pumps should not be considered “functioning ” unless they were operating for at least 70% of the time with a maximum of two weeks’ delay between breakdown and repair. Furthermore, in line with the MDG indicator definition that stipulates “use of improved water sources” to measure “access to improved water sources”, JMP measures and reports on the actual use of improved drinking water. It is also worth noting that the household surveys and censuses on which JMP relies also measure “use” and not “access” — since access involves many additional criteria other than use. 3. JMP Methodology For each country, data from surveys and censuses are plotted on a timescale from 1980 to the present. With these data points, a linear trend line based on least squares is drawn and from this line estimates are made for 1990, 1995, 2000, 2005 and 2008 (if possible). The total estimates are population weighted average of the urban and rural numbers. When necessary, JMP extrapolates the linear regression line up to two years before or after the earliest or latest data point. Outside these time limits, the extrapolated regression line is flat for up to four years. If the extrapolated regression line reaches 0% or 100% coverage or beyond, a flat...