Box 1 Calculation of the Water/sanitation, Assets, Maternal education, and Income (WAMI) index (Psaki et al.)

Water/sanitation

Using WHO definitions of access to improved water and improved sanitation, households with access to improved water or improved sanitation are assigned a score of 4 for each. Households without access to improved water or improved sanitation are assigned a score of 0 for each. These scores were summed

0–8

Assets

Eight priority assets were selected. For each asset, households were assigned a 1 if they have the asset and 0 if they do not have the asset. These scores were summed

0–8

Maternal education

Each child’s mother provided the number of years of schooling she had completed, ranging from 0 to 16 years. This number was divided by 2

0–8

Income

Monthly household income was converted to US dollars using the exchange rate from January 1, 2010. Income was divided into octiles using the following scores and cutoffs: 1(0–26), 2 (26.01–47), 3 (47.01–72), 4 (72.01–106), 5 (106.01–135), 6 (135.01–200), 7 (200.01–293), 8 (293 +)

0–8

TOTAL

Scores in water and sanitation, assets, mother´s education, and income were summed then divided by 32

0–1