builtin_references: Age-conditional reference distribution of D-score

builtin_referencesR Documentation

Age-conditional reference distribution of D-score


A data frame containing the age-dependent distribution of the D-score for children aged 0-5 years. The distribution is modelled after the LMS distribution (Cole & Green, 1992) or BCT model (Stasinopoulos & Rigby, 2022) and is equal for both boys and girls. The LMS/BCT values can be used to graph reference charts and to calculate age-conditional Z-scores, also known as DAZ.




A data.frame with 265 rows and 17 variables:

Name Label
pop Population, either "dutch", "gcdg" or "phase1"
age Decimal age in years
mu M-curve, median D-score, P50
sigma S-curve, spread expressed as coefficient of variation
nu L-curve, the lambda coefficient of the LMS/BCT model for skewness
tau Kurtosis parameter in the BCT model
P3 P3 percentile
P10 P10 percentile
P25 P25 percentile
P50 P50 percentile
P75 P75 percentile
P90 P90 percentile
P97 P97 percentile
SDM2 -2SD centile
SDM1 -1SD centile
SD0 0SD centile, median
SDP1 +1SD centile
SDP2 +2SD centile


The "dutch" references were calculated from the SMOCC data, and cover age range 0-2.5 years (van Buuren, 2014). The "gcdg" references were calculated from the 15 cohorts of the GCDG-study, and cover age range 0-5 years (Weber, 2019). The "phase1" references were calculated from the GSED Phase 1 validation data (GSED-BGD, GSED-PAK, GSED-TZA) cover age range 2w-3.5 years. The age range 3.5-5 yrs is linearly extrapolated and are only indicative.


Cole TJ, Green PJ (1992). Smoothing reference centile curves: The LMS method and penalized likelihood. Statistics in Medicine, 11(10), 1305-1319.

Van Buuren S (2014). Growth charts of human development. Stat Methods Med Res, 23(4), 346-368. https://stefvanbuuren.name/publication/van-buuren-2014-gc/

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. https://gh.bmj.com/content/bmjgh/4/6/e001724.full.pdf

Stasinopoulos M, Rigby R (2022). gamlss.dist: Distributions for Generalized Additive Models for Location Scale and Shape, R package version 6.0-3, https://CRAN.R-project.org/package=gamlss.dist

See Also




dscore documentation built on Jan. 22, 2023, 1:50 a.m.