R/builtin_references.R
builtin_references.Rd
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.
builtin_references
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
head(builtin_references)
#> pop age mu sigma nu tau P3 P10 P25 P50 P75 P90 P97
#> 1 dutch 0.0383 8.81 0.3126 1.3917 NA 3.15 5.07 6.91 8.81 10.57 12.07 13.49
#> 2 dutch 0.0575 10.59 0.2801 1.4418 NA 4.32 6.49 8.52 10.59 12.50 14.12 15.64
#> 3 dutch 0.0767 12.27 0.2526 1.4891 NA 5.61 7.96 10.10 12.27 14.28 15.97 17.56
#> 4 dutch 0.0958 13.87 0.2291 1.5331 NA 6.99 9.43 11.64 13.87 15.93 17.67 19.30
#> 5 dutch 0.1150 15.39 0.2089 1.5722 NA 8.42 10.89 13.13 15.39 17.47 19.23 20.89
#> 6 dutch 0.1342 16.83 0.1916 1.6049 NA 9.86 12.32 14.56 16.83 18.92 20.69 22.36
#> SDM2 SDM1 SD0 SDP1 SDP2
#> 1 2.78 5.94 8.81 11.39 13.76
#> 2 3.88 7.46 10.59 13.38 15.94
#> 3 5.12 8.98 12.27 15.20 17.87
#> 4 6.47 10.48 13.87 16.87 19.61
#> 5 7.89 11.95 15.39 18.43 21.21
#> 6 9.33 13.39 16.83 19.88 22.68