Qestion about the lower boundary in pcVPC calculation
Hi All,
I’m trying to understand what pcVPC did in PsN.
When I reading below paper,
“Martin Bergstrand, Andrew C. Hooker, Johan E. Wallin, and Mats O. Karlsson
Prediction-Corrected Visual Predictive Checks for Diagnosing Nonlinear
Mixed-Effects Models”
I got confused about the meaning of lb_ij(lower boundary) on equation (1).
pcY_ij=lb_ij+(Y_ij-lb_ij)*(pred_bin-lb_ij)/(pred_ij-lb_ij)
Yij = observation or prediction for the ith individual and jth time point,
pcYij = prediction-corrected observation or prediction,
PREDij = typical population prediction for the ith individual and jth time
point,
and PReEDbin = median of typical population predictions for the specific bin of
independent
variables.
For example, if a pk model was simulated with 3 different dose and the time is
real time not nominal time.
How to calculate lb_ij?
Below is a pcVPC simulated data example (not real)
ID
DV
TIME
strata_no
DOSE
1
2.0
0.90
1
1
1
12.6
3.10
1
1
1
2.8
5.00
1
1
1
1.5
8.00
1
1
1
1.0
12.00
1
1
2
1.0
0.90
2
2
2
22.3
6.10
2
2
2
12.0
5.10
2
2
2
3.0
8.30
2
2
2
1.0
12.00
2
2
3
1.0
1.00
3
3
3
40.1
3.10
3
3
3
11.7
5.40
3
3
3
6.6
8.00
3
3
3
2.0
12.00
3
3
Any help or suggestion is appreciated.
Thanks in advance.
Regards
Kevin