• Second, U5MR is known to be the result of a wide variety of inputs: for example, antibiotics to treat pneumonia; insecticide-treated mosquito nets to prevent malaria; the nutritional well-being and health knowledge of mothers; the level of immunization and oral rehydration therapy use; the availability of maternal and child health services, including antenatal care; income and food availability in the family; the availability of safe drinking water and basic sanitation; and the overall safety of the child’s environment. • Third, U5MR is less susceptible to the fallacy of the average than, for example, per capita gross national income (GNI). This is because the natural scale does not allow the children of the rich to be one thousand times more likely to survive, even if the human made scale does permit them to have one thousand times as much income. In other words, it is much more difficult for a wealthy minority to affect a nation’s U5MR, and this indicator therefore presents a more accurate, if far from perfect, picture of the health status of the majority of children and of society as a whole. The speed of progress in reducing child mortality can be assessed by calculating its annual rate of reduction (ARR). Unlike the comparison of absolute changes, ARR measures relative changes that reflect differences compared with the starting value. As lower levels of child mortality are reached, the same absolute reduction represents a greater percentage reduction. ARR therefore shows a higher rate of progress for a 10-point absolute reduction, for example, if that reduction happens at a lower level of child mortality versus a higher level over the same time period. A 10-point decrease in U5MR from 100 in 1990 to 90 in 2015 represents a reduction of 10 per cent, corresponding to an ARR of about 0.4 per cent, whereas the same 10-point decrease from 20 to 10 over the same period represents a reduction of 50 per cent, or an ARR of 2.8 per cent. (A negative value for the percentage reduction indicates an increase in U5MR during the period specified.) When used in conjunction with gross domestic product (GDP) growth rates, child mortality indicators and their rates of reduction can therefore give a picture of the progress being made by any country, area or region, over any period of time, towards the satisfaction of some of the most essential human needs. As Table 10 shows, there is no fixed relationship between the ARR of U5MR and the annual rate of growth in per capita GDP. Comparing these two indicators helps shed light on the relationship between economic advances and human development. Finally, the table gives the total fertility rate for each country and area and the corresponding ARR. It is clear that many of the nations that have achieved significant reductions in their U5MR have also achieved significant reductions in fertility. TABLES 12 AND 13. DISPARITIES BY RESIDENCE AND BY HOUSEHOLD WEALTH Stunting: Beginning in 2016, The State of the World’s Children no longer includes the disparities in underweight (weight-for-age) prevalence, and instead provides the breakdown for stunting (height-for-age). This is because stunting has gained precedence as a key global marker of child undernutrition and is now a focus of the SDG agenda, while underweight is no longer among the indicators to be used to track country, regional or global progress on nutrition. Underweight had been the indicator used to track MDG target 1.c. on nutrition of children under the age of 5 years, however, even during the MDG period, UNICEF and other partners had focused on progress in stunting as the marker of success. THE STATE OF THE WORLD’S CHILDREN 2016 117