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Estimation methods

JMP estimates for basic and safely managed services

JMP estimates are based on a simple classification of drinking water sources and sanitation facilities into improved and unimproved types. This information is widely available from national household surveys, censuses and administrative systems. For MDG reporting the JMP estimated the proportion of population using improved and unimproved types of facilities. For SDG reporting the JMP has introduced new information on service levels and further classified improved facilities into three categories: limited, basic or safely managed services. JMP estimates of the population using basic services are used for global tracking of progress towards SDG target 1.4. JMP estimates of the population using safely managed services are used for global tracking progress towards SDG targets 6.1 and 6.2.

Drinking water

Households using improved drinking water sources which are located on premises, with water available when needed, and free from contamination*, are classified as having safely managed services. Households not meeting all of these criteria, but using an improved source with water collection times of no more than 30 minutes per round trip are classified as having basic services, and those using improved sources with water collection times exceeding 30 minutes are classified as limited services.

*For global monitoring purposes, the priority water quality parameter will be the absence of faecal indicator bacteria (E. coli or thermotolerant coliforms). Data on arsenic and fluoride will also be used where available

Sanitation

Households using improved sanitation facilities which are not shared with other households are classified as having ‘basic’ services, and those using improved sanitation facilities shared with other households are classified as having ‘limited’ services. To be classified as safely managed households must use an improved sanitation facility which is not shared and where excreta are either safely disposed of in situ or removed off-site and treated. Sewage that undergoes at least secondary treatment (or primary treatment with a long ocean outfall) is counted as safely managed. Information on faecal sludge management can include containment, emptying, delivery to treatment and treatment with appropriate technologies.

Hygiene

Hygiene was not included in the MDGs but is explicitly referenced in SDG target 6.2. Through international consultations on hygiene, the presence of a basic handwashing facility with soap and water has been identified as the closest measurable proxy for hygiene and therefore has been included in the SDG indicator as the top global priority. This proxy measure has been increasingly included in household surveys, and represents a more reliable indicator than reported handwashing behaviour. For global reporting the JMP uses national surveys to estimate the proportion of households with a handwashing facility with soap and water available at home.

Estimation method

The JMP generates rural, urban and national estimates for each country by drawing a line of best fit between all available data points. Simple linear regression using least squares method of minimizing the variability of the data points is used to estimate the proportion of the population using each of the following facility types for a given reference year between 2000 and 2015:

  • Improved drinking water
    • Improved within 30 minutes (basic or safely managed)
    • Improved over 30 minutes (limited)
    • Unimproved water
    • Surface water
  • Improved sanitation
    • Improved and not shared (basic or safely managed)
    • Improved and shared (limited)
    • Unimproved
    • Open defecation
  • Handwashing facility with soap and water
    • Facility observed with soap and water available
    • Facility without soap or water
    • No facility

To calculate safely managed drinking water the JMP estimates the proportion of improved drinking water sources (piped and non-piped) which are:

  • on premises,
  • available when needed, and
  • free from contamination.

These values are multiplied by the proportion of the population using improved drinking water sources, to find the population using improved water sources that are on premises, available when needed, and free from contamination. Finally, to be conservative, the JMP uses the minimum of these three values, wherever available, to estimate coverage of safely managed drinking water services.

To calculate safely managed sanitation the JMP estimates, like in the MDG period, the proportion of improved sanitation facilities not shared with other households (sewer connections, septic tanks and other improved facilities such as improved pit latrines) from which excreta are

  • safely disposed in situ (contained and not emptied, or emptied and buried on site), or
  • removed from the home through sewer lines and treated at a treatment plant, or
  • emptied from non-sewered facilities, transported to a treatment plant and treated.

The proportion reaching treatment is adjusted based on the proportion of wastewater and faecal sludge treated.

While the data required to estimate access to basic drinking water, sanitation and handwashing facilities are readily available for most countries, the JMP has not always been able to find data from all countries in order to estimate safely managed drinking water and sanitation services. The JMP will only make an estimate if data are available for at least 50% of the relevant population and will indicate the completeness of the data underlying each country estimate.