Returns the age-interpolated median of the phase1 references
based on LF & SF in GSED-BGD, GSED-PAK, GSED-TZA. This function is used
to set prior mean under keys "293_0" and "gsed2212".
count_mu_phase1(t)A vector of length length(t) with the median of the GCDG references.
Decimal age, numeric vector
Stef van Buuren, on behalf of GSED project
The interpolation is done in two rounds. First round: Calculate D-scores using .gcdg prior-mean, calculate reference, estimate round 1 parameters used in this function. Round 2: Calculate D-score using round 1 estimates as the prior mean (most differences are within 0.1 D-score points), recalculate references, estimate round 2 parameters used in this function.
Round 1: Count model: <= 9MN: 21.3449 + 26.4916 t + 7.0251(t + 0.2) Count model: > 9Mn & <= 3.5 YR: 14.69947 - 12.18636 t + 69.11675(t + 0.92) Linear model: > 3.5 YRS: 61.40956 + 3.80904 t
Round 2: Count model: < 9MND: 20.5883 + 27.3376 t + 6.4254(t + 0.2) Count model: > 9MND & < 3.5 YR: 14.63748 - 12.11774 t + 69.05463(t + 0.92) Linear model: > 3.5 YRS: 61.37967 + 3.83513 t
The working range is 0-3.5 years. After the age of 3.5 years, the function will increase at an arbitrary rate of 3.8 D-score points per year.