The Child Health Index is calculated as follows. For Access to At Least Basic Sanitation and Access to At Least Basic Water, the proximity-to-target measure is equal to the reported percentage. For example, if a country has 84% of its population with access to adequate sanitation, it is considered to have a proximity-to-target score of 84. For child mortality, we compute the ratio of the measured probability of dying in a given country to the highest observed probability of dying in each year. To calculate the child mortality proximity-to-target score, it is necessary to have a benchmark for the highest reported child mortality as a worst performance lower bound. In the time series data reported by UN IGME between 2010 and 2018, Haiti had the highest reported mortality rate between ages 1 and 4 (4q1), at 134.6 per 1,000, owing to the exceptionally high mortality during the 2010 Earthquake. Because this was an exceptional event that killed an estimated 100,000 to 300,000 people, it did not seem appropriate to use that as the highest reported mortality rate. So Chad was chosen as the next highest reported rate in 2010, since Chads rate of 70.8 per 1,000 in 2010, was consistent with the time series of child mortality data reported for the country. The formula for calculation is as follows: 100 - ((country value) / 70.8) * 100). For example, a country whose children in the 1-5 age group have a probability of dying of 43.3 per 1000 would have a proximity-to-target score of 38.8 (or 100 - ((43.3/70.8) * 100)).
For Natural Resource Protection, all scores by biome are capped at 17%, which is the target established at the 10th Conference of Parties of the Convention on Biological Diversity (Nagoya, Japan). The scores are capped so that greater than 17% protection in a given biome does not offset less than 17% protection in another biome. Since the range of protection levels across all countries is from 017%, the proximity to target scores is then calculated as the ratio of the weighted biome protection percentage to 17%, multiplied by 100. Thus, a country with 5% weighted biome protection would be calculated as follows: 5/17 = 0.29411; 0.29411 x 100 = 29.41.