UN IGME 2015. The Inter-agency Group for Child Mortality of Estimation, which includes representatives from UNICEF, WHO, the World Bank and the United Nations Population Division, produces trends of under-five mortality with standardized methodology by group of countries depending on the type and quality of source of data available. For countries with adequate trend of data from civil registration, the calculations of under-five and infant mortality rates are derived from a standard period abridged life table. For countries with survey data, under-five mortality rates are estimated using the Bayesian B-splines bias-adjusted model. These under-five mortality rates have been estimated by applying methods to all Member States to the available data from Member States that aim to ensure comparability of across countries and time; hence they are not necessarily the same as the official national data.