The JMP uses a standard classification and estimation method to compare progress across countries
Estimations begin with the identification of nationally representative data sources that contain information on the use of water and sanitation services and the availability of handwashing facilities in the home. For most countries this information is collected from households during interviews conducted by national statistical offices.
The new SDG indicators for safely managed drinking water and sanitation build on the facility type classifications, by integrating data on service levels usually from administrative sources and household surveys.
A simple linear regression estimation method is then used to estimate the population using different levels of service using the JMP ladders for drinking water, sanitation and hygiene.
To support greater harmonization of data, the JMP has devised sets of core questions for water, sanitation and hygiene at households, schools and health centres.