Table 1. Early Childhood Development Index items.

Domain and Item	Included in Present Study?	Construct Measured	Age Appropriate?	Similar Item Included in ASQ-III or SDQ for 36-to 60-mo Age Range?	Failure of Attainment Acknowledged by AAP as “Possible Sign of Developmental Delay” for Ages 3–4 y?	Rationale for Inclusion/Exclusion
Literacy-numeracy						Measures of academic knowledge rather than general capacity; items too difficult for young children
Can your child identify or name at least ten letters of the alphabet?	No	Early literacy	No	ASQ-III (60 mo), though four letters only	No
Can your child read at least four simple, popular words?	No	Early literacy	No	No	No
Does your child know the name and recognize the symbol of all numbers from 1 to 10?	No	Early numeracy	No	ASQ-III (54–60 mo), though two numbers only	No
Learning/cognition						Age-appropriate measures of cognition
Does your child follow simple directions on how to do something correctly?	Yes	Cognition	Yes	ASQ-III (36–60 mo)	Yes, “cannot understand two-part commands”
When given something to do, is your child able to do it independently?	Yes	Cognition	Yes	No	No, though “shows more independence” listed as positive milestone
Physical development						“Too sick to play” not a measure of development; pincer grasp appropriate for under 12 mo
Is your child sometimes too sick to play? (reverse coded)	No	Health	Yes	No	No
Can your child pick up a small object with two fingers, like a stick or a rock from the ground?	No	Fine motor	No	No	Yes, “cannot grasp a crayon between thumb and fingers”
Socioemotional development						Age-appropriate measures of socioemotional development
Does your child kick, bite, or hit other children or adults? (reverse coded)	Yes	Aggressive behavior	Yes	SDQ (36–60 mo), focus on fighting/bullying	Yes, “exhibits aggressive behavior”
Does your child get easily distracted? (reverse coded)	Yes	Attention	Yes	SDQ (36–60 mo)	Yes, “is easily distracted”
Does your child get along well with other children?	Yes	Social competence	Yes	ASQ-III (60 mo), focus on sharing and taking turns; SDQ (36–60 mo), focus on being well liked	Yes, “shows little interest in playing with other children”

All ECDI items scored as yes (one)/no (zero). Children were classified as “low development” for a domain if they received a score of zero on more than one item within the domain.

The Ages & Stages Questionnaire, Third Edition, and the Strengths and Difficulties Questionnaire were chosen as comparators because they are well-validated measures of early development used across high-, middle-, and low-income country contexts.

AAP, American Academy of Pediatrics; ASQ-III, Ages & Stages Questionnaire, Third Edition; SDQ, Strengths and Difficulties Questionnaire.