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Published on: 24/06/2019

"15 years to make history, 5 years to make change" is one of IRC's slogans. It refers to the fact that the World has some five years – up to 2020 – to make the necessary plans, develop financing mechanisms, and strengthen the systems needed to speed up the delivery of water and sanitation services in the subsequent five years. In parallel, many countries would need to rapidly increase the rate with which new access is created during these first five years. Otherwise, they would not be able to reach universal coverage.

The recent JMP report, and the underlying databases, are really a fantastic resource to dig into this question. For example in figure 30 they indicate whether countries are making sufficient progress to achieve universal access to at least basic services by 2030. This analysis is based on linear regression and extrapolation. This means that a regression analysis is carried out based on the values obtained through the household surveys that form the source data, to make estimates levels of access levels now and in the past. This linear regression can then be extrapolated to estimate levels of access by 2030.

Sanitation market in India
Sanitation market in India

A limitation of this method is that it is not possible to capture rapid increases (or decreases) in access levels. The JMP report illustrates the apparent non-linear trend in ending open defecation in India (see page 22 of the report), as a result of the efforts of the Swachh Bharat Mission. Recent survey results from India report a rapid decrease in the percentage of the population practising open defecation. That is a clear sign of the type of change we would need to achieve the SDGs. Linear regression analyses cannot properly identify these non-linear trends.

This made me wonder whether there are any other countries where rapid increases in access are happening, or where other non-linear patterns in access growth are happening, such as levelling off of the growth rate.

To do that analysis, I focused on the 'rate of change', which is the average annual rate with which access to water or sanitation changes. In mathematical terms, it is the slope of the regression line. For example, for the first country in the JMP database, Afghanistan, the rate of change in access to 'at least basic' water supply services is calculated as 2.31. Over the period 2000-2017, on average 2.31 percentage-point of the Afghani population gained access to at least basic water services. However, in the previous JMP report (which covered the period 2000-2015) this was calculated to be 2.39. This means, that the surveys that were added to the regression analysis in the period 2015-2017 were such that they reduce the slope of the regression line a bit, from 2.39 to 2.31.

This difference between the rate of change published in the current report (covering the 2000-2017 period) and the one in the previous report (over the 2000-2015 period) is an indication of increasing or slowing down of rate of change. If the difference is positive, there is a more rapid increase in services; if the difference is negative, the rate at which access is growing is slowing down.

In fact, in some cases the estimates for past access level may be adjusted up- or downwards. In the 2017 report, Afghanistan's level of access to at least basic water in 2000 was estimated to be 28%; in the 2019 report, Afghanistan's estimated level of access to at least basic water in 2000 was adjusted downwards a bit to 27%. This is a case of a small shift in the estimated baseline due to a change in the slope of the regression line. This has then implications for the projected level of access by 2030. Based on the 2017 estimates, Afghanistan was projected to have 99% access to at least basic water by 2030; this would now be adjusted downwards a bit to 97%.

In Afghanistan, this adjustment is minor, probably within the margins of error. But in the case of India, above, the adjustment due to the non-linear change is major. In order to assess whether there are more countries with rapid increase in access, like India, I have calculated the projected access to at least basic service (both water and sanitation) by 2030, based on the 2017 report data and on the 2019 report, and compared the two figures. Based on that, I classified the countries as follows:

  • Projected to achieve: countries that currently already achieved universal access to at least basic services (defined as more than 99%) or that are projected to achieve universal access by 2030 both based on the 2017 and the 2019 report.
  • Upward adjusted projection: countries for which the estimated level of access in 2030 has been adjusted upwards by more than 5 percentage-points as compared to what was estimated in the 2017 report.
  • Stable projection: countries for which the estimated level of access in 2030 has not been adjusted more than 5 percentage-points upward or downward as compared to what was estimated in the 2017 report. They are countries that have a stable linear growth path.
  • Downward adjusted projection: countries for which the estimated level of access in 2030 has been adjusted downwards by more than 5 percentage-points as compared to what was estimated in the 2017 report.

Countries classified as upward or downward are countries where potentially non-linear growth is happening. The exercise yielded the following results for 'at least basic water':

Table 1: number of countries classified by change in growth rate in access to at least basic water services

As can be seen, a total of 100 countries have achieved at least basic water, or would be projected to achieve that by 2030. Of the countries with an upward adjusted forecast, 8 would achieve universal coverage by 2030 and another 3 would come close (more than 95%). Of the ones with a stable growth projection, the vast majority (32) would end with more than 95% access. The countries with downward adjusted forecasts are found in the lower ranges of access.

For sanitation, the results are different:

Table 2: number of countries classified by change in growth rate in access to at least basic sanitation

These results show a much lower number of countries that have achieved or are projected to achieve universal access by 2030. The countries with a stable projection can be grouped in two clusters: ones with a projected very low coverage (21 countries projected to reach less than 50%) and ones projected to reach more than 90% (42 countries in total). The former are countries that start from a very low base, and have not started accelerating; the latter are countries that are gradually growing access to high levels. The countries with upward and downward adjustments are found in all coverage levels.

The question remains whether the countries classified as 'upward' or 'downward' are really experiencing non-linear growth in the rate of change. To do so I reviewed the underlying country data sheets, available from the JMP website. This showed essentially three groups of countries:

  • Countries with few data points. Most of the countries identified as 'upward' or 'downward' are least-developed countries – many fragile states - where comparatively few surveys have been done. As a result the regression lines change relatively a lot with every extra data point added. The results of a single survey have a relatively high influence on the regression line and result in relatively large upward or downward movements in the trend line. Countries in this group include for example Angola and Botswana, which had only one survey during the past two years, and had few preceding data points. The results of these recent surveys caused relatively strong changes in the slope of the regression line, resulting in the adjusted forecast. But, the results don't show a non-linear growth pattern. This is the case for most countries classified as 'upward' or 'downward'. They have too few data points to even see signs of non-linear growth. This also means that much care should be taken in the linear projection of estimates towards the future.
  • Countries whose estimates are affected by the factor 'accessible within 30 minutes'. The definition of 'at least basic services' depends on two factors: using an improved water source and that source being accessible within 30 minutes. The percentage of people with access to improved services has been tracked for a long time in most countries. In many countries, this factor has only been tracked through surveys in the period 2015-2017. In some of the countries identified as 'upward' or 'downward' the factor of accessibility affected the regression line. This is best illustrated by the case of Burkina Faso, where the regression line for improved services shows an ever increasing trend, and the one for 'at least basic' a downward one. The three most recent survey results provide data on time spending, whereas there was only one other data point prior to that, which was higher. In Uganda, the opposite happens, with recent data points showing relatively high percentages of people accessing water within 30 minutes. These are thus countries where there is no non-linear growth happening, but an upward or downward adjustment based on more data on accessibility within 30 minutes.
  • Countries with first signs of non-linear growth. Finally, there are the countries where the underlying surveys show a non-linear growth pattern, and thereby resulting in a large shift in the slope of the regression line. These are all countries experiencing non-linear growth for 'at least basic sanitation' not 'at least basic water'. Apart from India, they are Nepal, Bolivia and Cambodia. Figure 1 shows for example the regression lines for rural sanitation in Bolivia, showing the peak in the last few surveys. Nigeria is another case with non-linear growth. Access to at least basic sanitation showed negative growth up till about 2010, and then linear growth up again since then. This is through a combination of steady increase in access to improved sanitation and a reduction of shared sanitation.

Figure 1: data points and regression line for access to at least basic sanitation in rural areas of Bolivia (Source: JMP country sheet for Bolivia)

Of the five years to make change, we now have data of 2 years. These show that in most countries, no drastic change is happening. Arguably, that is not even needed in many countries with respect to water supply. Around three-quarters of the countries are projected to reach more than 95% access to at least basic water services. But for the countries where change is most needed, i.e. ones which currently have low levels of access, no signs of change were found. In fact, they are also the countries that have least data to make estimates of past, current and future levels of access.

For sanitation, more change is needed. Only about half of all countries would achieve near universal access to basic services by 2030. A big group of countries would really need to drastically increase access as they are stuck with stable growth at very low levels of access. But there are also signs of hope. India is of course a big inspiration, and this exercise has also identified Bolivia, Cambodia, Nepal and Nigeria as countries where signs of non-linear growth are happening. Hopefully, the momentum to rapidly increase access can be maintained in these countries, so they can write sanitation history.

Acknowledgements. Thanks to Marieke Adank for her review.


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