This methodological note outlines the methodology and policies applied to harmonise 244 survey datasets, which form the basis for generating the harmonised level estimates and their changes over time in multidimensional poverty for 88 countries and 882 subnational regions. Forty of the 88 countries have data for one period spanning two points in time, while poverty trends in 35 countries are based on three points in time. Nine countries (Benin, Bolivia, Eswatini, Kyrgyzstan, Nigeria, the Philippines, Senegal, Tanzania and Thailand) have results spanning four points in time. One country (Ghana) provides trends across five time periods, while Mexico, Peru and Nepal have the longest coverage, with trends for six time periods.