builtin_references {dscore}

Age-conditional reference distribution of D-score

Description

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.

Usage

builtin_references

Format

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

Details

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.

References

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()

Examples

head(builtin_references)