Dear Norman,

 

Regarding: " (I suspect the "DV_matrix.csv" and
"vpc_simulation.1.npctab.dta" in "m1" folder are the raw simulated data, but
want to  refer to relevant document to understand how these files are
organized.)", and other questions I believe that the psn user guide for
npc/vpc (npc_vpc_userguide.pdf) contains the information you seek.

 

Best regards,

Mats

 

Mats Karlsson, PhD

Professor of Pharmacometrics

 

Dept of Pharmaceutical Biosciences

Faculty of Pharmacy

Uppsala University

Box 591

75124 Uppsala

 

Phone: +46 18 4714105

Fax + 46 18 4714003

 

From: owner-nmus...@globomaxnm.com [mailto:owner-nmus...@globomaxnm.com] On
Behalf Of Norman Z
Sent: 09 October 2012 16:31
To: nmusers@globomaxnm.com
Subject: [NMusers] VPC question

 

Dear NMusers,

 

I am using PsN to conduct VPC. A "vpc_results.csv" was generated by PsN,
where the percentiles of real and simulated data were reported. Generally,
these percentiles plus the observed data were used for the VPC plot. My
question is how to calculate number of observation outside the 90%
prediction interval (PI). I am thinking about two way to do this.

 

First, I may use the NPC results provided by the "vpc_results.csv" file,
e.g.

 

NPC results                            

bin 3: 15 observations                        

points below PI (count)       points below PI (%)     ...

         0% PI             7
46.66667     ...

        40% PI            5
33.33333     ...

        80% PI            1
6.66667      ...

        90% PI            0                                              0
...

        95% PI            0                                              0
...

 

Should the numbers in this table be used to obtain the observation outside
the 90% PI? If so, how can they be used? 

If not, shall I calculate the observation outside the 90% PIs of each bin
using R?

 

Second, I can calculate the 90% PIs for each time point (e.g. 1.1h, 1.3h,
etc) from the raw simulated data and compare the 90% PIs with the
observation at one particular time point. Would the second strategy be more
accurate than calculate the observation outside the 90% PIs of each binned
time interval (e.g. 1-2 h, 2-3 h)? If this is the case, where can I find the
raw simulated data? (I suspect the "DV_matrix.csv" and
"vpc_simulation.1.npctab.dta" in "m1" folder are the raw simulated data, but
want to  refer to relevant document to understand how these files are
organized.)

 

Thanks for your help.

 

Norman

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