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[NMusers] Qestion about the lower boundary in pcVPC calculation

From: Wang Kevin <fengdubianbian_at_hotmail.com>
Date: Sat, 28 Apr 2018 13:19:40 +0000

Hi All,

Ií»m trying to understand what pcVPC did in PsN.
When I reading below paper,
í░Martin Bergstrand, Andrew C. Hooker, Johan E. Wallin, and Mats O. Karlsson
Prediction-Corrected Visual Predictive Checks for Diagnosing Nonlinear
Mixed-Effects Modelsí▒
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

Received on Sat Apr 28 2018 - 09:19:40 EDT

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