← Methodology

Evidence & Sources

Our developmental intelligence draws on three categories of evidence — each with a distinct role in how we derive milestone windows, confidence scores, and curriculum alignment.

30

normative studies

386k+

children with response data

66

countries represented

3

clinical instruments

2

curriculum frameworks

Normative Research

Large-scale population studies that define what is developmentally typical across diverse global contexts. These are the backbone of our age-window predictions and confidence scores — they tell us what most children can do, and when.

Longitudinal studyRestricted

Stanford SHQ

Stanford University · 2021

Sample
21.9k+
Countries
1
Milestones covered
422

Ages birth6yr

Normative instrumentOpen

WHO GSED

World Health Organization · 2023

Sample
Countries
9
Milestones covered
155

Ages birth3yr

Growth referenceOpen

WHO MGRS

World Health Organization · 2006

Sample
8.5k+
Countries
6
Milestones covered
6

Ages birth5yr

Normative instrumentOpen

CREDI

Harvard Center on the Developing Child · 2020

Sample
14.1k+
Countries
17
Milestones covered
108

Ages birth3yr

Normative instrumentOpen

MELQO

UNESCO / UNICEF · 2017

Sample
Countries
12
Milestones covered
30

Ages 4yr6yr

Normative instrumentOpen

ECDI 2030

UNICEF · 2020

Sample
Countries
Milestones covered
8

Ages 2yr4yr 11mo

Population surveyOpen

MICS6

UNICEF · 2019

Sample
335.2k+
Countries
66
Milestones covered

Ages 2yr4yr 11mo

Normative study (clinical)Restricted

IDB Bogota

Inter-American Development Bank · 2020

Sample
1.3k+
Countries
1
Milestones covered

Ages birth3yr

national registryOpen

Japan MHLW

こども家庭庁 / Children & Families Agency, Japan (descended from MHLW 厚生労働省 administration pre-2023 reorg) · 2026

Sample
Countries
1
Milestones covered
126

Ages 1mo7yr

national registryOpen

HK FHS

Department of Health, Hong Kong SAR · 2018

Sample
Countries
1
Milestones covered

Ages birth6yr

parent screenOpen

M-CHAT-R/F

Robins, Fein & Barton (M-CHAT-R/F LLC) · 2014

Sample
Countries
1
Milestones covered
11

Ages 1yr 4mo2yr 6mo

instrumentRestricted

Paul H. Brookes Publishing / Brookes Publishing Co. ·

Sample
Countries
Milestones covered

Ages 2mo5yr 6mo

instrumentRestricted

Paul H. Brookes Publishing ·

Sample
Countries
Milestones covered

Ages 1mo6yr

instrumentRestricted

Pearson / PAR ·

Sample
Countries
Milestones covered

Ages 1yr3yr

instrumentRestricted

Pearson Assessment (formerly NCS Pearson) ·

Sample
Countries
Milestones covered

Ages 4yr21yr 11mo

instrumentRestricted

PAR (Psychological Assessment Resources) ·

Sample
Countries
Milestones covered

Ages 2yr5yr 11mo

instrumentRestricted

ASEBA (Achenbach System of Empirically Based Assessment) ·

Sample
700+
Countries
Milestones covered

Ages 1yr 6mo5yr 11mo

instrumentRestricted

Kaplan Early Learning Company / Devereux Center for Resilient Children ·

Sample
Countries
Milestones covered

Ages 1mo3yr

instrumentRestricted

Hogrefe Ltd. (UK); distributed by Pearson Australia (AUS), PAA (AUS) ·

Sample
426+
Countries
Milestones covered

Ages birth6yr

instrumentRestricted

INTERGROWTH-21st Project / Nuffield Department of Obstetrics & Gynaecology, University of Oxford ·

Sample
1.2k+
Countries
Milestones covered

Ages 1yr 10mo2yr 6mo

instrumentRestricted

Pearson Education Ltd. ·

Sample
Countries
Milestones covered

Ages 3yr16yr

instrumentRestricted

Paul H. Brookes Publishing ·

Sample
Countries
Milestones covered

Ages 8mo1yr 6mo

instrumentRestricted

Paul H. Brookes Publishing ·

Sample
1.5k+
Countries
Milestones covered

Ages 1yr 4mo3yr 1mo

instrumentRestricted

Pearson (formerly AGS) ·

Sample
Countries
Milestones covered

Ages birth5yr 8mo

instrumentRestricted

PEDStest.com LLC ·

Sample
Countries
Milestones covered

Ages birth8yr

instrumentRestricted

Pearson / PsychCorp ·

Sample
Countries
Milestones covered

Ages birth6yr 11mo

instrumentRestricted

Tufts Medical Center / TEAM UP Center ·

Sample
Countries
Milestones covered

Ages 1mo5yr 5mo

instrumentRestricted

Pearson ·

Sample
Countries
Milestones covered

Ages birth90yr

instrumentRestricted

Pearson Assessment (NCS Pearson) ·

Sample
1.7k+
Countries
Milestones covered

Ages 2yr 6mo7yr 7mo

open activity libraryRestricted

Vroom

Bezos Family Foundation · ongoing (program est. ~2014)

Sample
Countries
1
Milestones covered

Ages birth5yr

Clinical Assessment Instruments

Validated tools used by paediatricians, developmental specialists, and early childhood practitioners to evaluate individual children against established norms. We map their assessment constructs to our canonical milestones to validate coverage and enable cross-instrument comparison.

Curriculum Frameworks

National and institutional learning standards from governments and educational bodies worldwide. We use them to align our curriculum skills across cultures and to map what practitioners expect children to learn, not just observe developmentally.