The dscore package implements several tools needed to calculate the D-score, a numerical score that measures generic development in children.


This study was supported by the Bill & Melinda Gates Foundation. The contents are the sole responsibility of the authors and may not necessarily represent the official views of the Bill & Melinda Gates Foundation or other agencies that may have supported the primary data studies used in the present study.

The authors wish to recognize the principal investigators and their study team members for their generous contribution of the data that made this tool possible and the members of the Ki team who directly or indirectly contributed to the study: Amina Abubakar, Claudia R. Lindgren Alves, Orazio Attanasio, Maureen M. Black, Maria Caridad Araujo, Susan M. Chang-Lopez, Gary L. Darmstadt, Bernice M. Doove, Wafaie Fawzi, Lia C.H. Fernald, Günther Fink, Emanuela Galasso, Melissa Gladstone, Sally M. Grantham-McGregor, Cristina Gutierrez de Pineres, Pamela Jervis, Jena Derakhshani Hamadani, Charlotte Hanlon, Simone M. Karam, Gillian Lancaster, Betzy Lozoff, Gareth McCray, Jeffrey R Measelle, Girmay Medhin, Ana M. B. Menezes, Lauren Pisani, Helen Pitchik, Muneera Rasheed, Lisy Ratsifandrihamanana, Sarah Reynolds, Linda Richter, Marta Rubio-Codina, Norbert Schady, Limbika Sengani, Chris Sudfeld, Marcus Waldman, Susan P. Walker, Ann M. Weber and Aisha K. Yousafzai.

User functions

The available functions are:

get_itemnames()Extract item names from an itemtable
order_itemnames()Order item names
sort_itemnames()Sort item names
decompose_itemnames()Get four components from itemname
get_itemtable()Get a subset from the itemtable
get_labels()Get labels for items
rename_gcdg_gsed()Rename gcdg into gsed lexicon
dscore()Estimate D-score and DAZ
dscore_posterior()Calculate full posterior of D-score
get_tau()Get difficulty parameters from item bank
daz()Transform to age-adjusted standardized D-score
zad()Inverse of daz()
get_reference()Get D-score age-reference
get_age_equivalent()Translate difficulty to age

Built-in data

The package contains the following built-in data:

builtin_itembank()A data.frame containing the difficulty estimates of items according to final Rasch models.
builtin_itemtable()A data.frame containing names and descriptions of items from 22 instruments.
builtin_references()A data.frame with LMS reference values used to transform from D-score to DAZ, DAZ to D-score.
milestones()A small demo dataset with PASS/FAIL responses from 27 preterms, measured at various ages between birth
and 2.5 years.


Jacobusse, G., S. van Buuren, and P.H. Verkerk. 2006. “An Interval Scale for Development of Children Aged 0-2 Years.” Statistics in Medicine 25 (13): 2272–83.

Van Buuren S (2014). Growth charts of human development. Stat Methods Med Res, 23(4), 346-368.

Weber AM, Rubio-Codina M, Walker SP, van Buuren S, Eekhout I, Grantham-McGregor S, Caridad Araujo M, Chang SM, Fernald LCH, Hamadani JD, Hanlon A, Karam SM, Lozoff B, Ratsifandrihamanana L, Richter L, Black MM (2019). The D-score: a metric for interpreting the early development of infants and toddlers across global settings. BMJ Global Health, BMJ Global Health 4: e001724.

GSED team (Maureen Black, Kieran Bromley, Vanessa Cavallera (lead author), Jorge Cuartas, Tarun Dua (corresponding author), Iris Eekhout, Gunther Fink, Melissa Gladstone, Katelyn Hepworth, Magdalena Janus, Patricia Kariger, Gillian Lancaster, Dana McCoy, Gareth McCray, Abbie Raikes, Marta Rubio-Codina, Stef van Buuren, Marcus Waldman, Susan Walker and Ann Weber). 2019. “The Global Scale for Early Development (GSED).” Early Childhood Matters.