Re: [External] Re: [NMusers] M3 method - WRES, and CWRES

2020-09-05 Thread Bach, Thanh H Y
I have a follow-up question on CWRES with M4 method.

I was able to run my model with M3 method, I got NPDE and CWRES (with MDVRES=1) 
calculated just fine. Then I changed to M4 method by adding YLO to the non-BLQ 
data, the model stilled converged but in the output table, some of the subjects 
had CWRES = 0 and NPDE was a constant (around 3). The problem with CWRES and 
NPDE is not specific to subjects with BLQ observations, but rather, it followed 
a pattern like this: CWRES and NPDE was calculated for subjects number 1, 3, 5, 
7, etc. and not calculated for subjects 2, 4, 6, 8, etc.

I suspected that YLO option was the cause, so I ran the model with M2 method. 
Indeed, all CWRES was 0.

This might not be a new problem, but I searched through the NMusers archives 
and most discussions focused on M3 only. Is there any reason why there is less 
focus on M2 and M4?

Thank you


From: owner-nmus...@globomaxnm.com  on behalf of 
Matthew Fidler 
Sent: Saturday, September 5, 2020 10:17 AM
To: Bauer, Robert 
Cc: nmusers@globomaxnm.com 
Subject: [External] Re: [NMusers] M3 method - WRES, and CWRES

Thank you Bob,

The NPDE 2.0 manual discusses the methods that NPDE uses to handle BLQ, 
including replacing values with pred, ipred, or lloq, or simulating from a 
uniform random value while calculating the NPDE (cdf method).  The NONMEM 
manual doesn't mention the method used.  My guess is the cdf method.

I realize that no one has answered Mu'taz's question.

As far as if the CWRES is appropriate for BLQ data, the CWRES method uses the 
FOCEi approximation to calculate residuals.  However with M3/M4 and other 
methods the likelihood for these points is not the FOCEi objective function but 
the M3/M4 likelihood so anything you do here with CWRES doesn't follow or add 
to the likelihood observed during minimization.  Therefore in my opinion, there 
will be bias of some sort here.


Best Regards,

Matt.

On Thu, Sep 3, 2020 at 3:06 PM Bauer, Robert 
mailto:robert.ba...@iconplc.com>> wrote:

Matt:

The NPDE and NPD systems in NONMEM are described in the nm744.pdf manual ( 
https://nonmem.iconplc.com/nonmem744 ), pages 70-75, and follow along the work 
of Comet, Brendel, Ngyuen, Mentre, etc.  The NPDE R package is not used within 
NONMEM.





Robert J. Bauer, Ph.D.

Senior Director

Pharmacometrics R

ICON Early Phase

820 W. Diamond Avenue

Suite 100

Gaithersburg, MD 20878

Office: (215) 616-6428

Mobile: (925) 286-0769

robert.ba...@iconplc.com<mailto:robert.ba...@iconplc.com>

www.iconplc.com<http://www.iconplc.com>



From: owner-nmus...@globomaxnm.com<mailto:owner-nmus...@globomaxnm.com> 
mailto:owner-nmus...@globomaxnm.com>> On Behalf 
Of Matthew Fidler
Sent: Thursday, September 3, 2020 6:08 AM
To: Jeroen Elassaiss-Schaap (PD-value B.V.) 
mailto:jer...@pd-value.com>>
Cc: Bill Denney 
mailto:wden...@humanpredictions.com>>; Mu'taz 
Jaber mailto:jaber...@umn.edu>>; 
nmusers@globomaxnm.com<mailto:nmusers@globomaxnm.com>
Subject: Re: [NMusers] M3 method - WRES, and CWRES



Hi everyone,



As an aside, nlmixr's upcoming release (that supports censoring) simulates a 
value using a truncated normal based on the ipred, variance at that point and 
the censoring column to produce an observation.  This observation is used to 
calculate RES, WRES, CWRES.  It is flagged so you can see which values use this 
approach.  In theory, since this is simulated from the IPRED/truncated the 
CWRES would be likely follow the distribution closer.



I'm unsure if the new NONMEM uses this approach.



Another question from my end is the NPDE:  There are many methods to handle BLQ 
values with NPDE R package, does anyone know which NONMEM uses?  Or do you need 
to use the NPDE package to get these values from NONMEM?



Matt.







On Wed, Sep 2, 2020 at 2:09 AM Jeroen Elassaiss-Schaap (PD-value B.V.) 
mailto:jer...@pd-value.com>> wrote:

Hi Mutaz, Bill,

It might be useful to use NPDEs, as discussed in 
https://www.cognigen.com/nmusers/2019-February/7376.html;  the whole thread is 
worthwhile reading. NPDEs can be calculated also for BQL values.

Bill -thanks for pointing to excellent post of Matt! I would take as most 
important point that CWRES for non-BQL values, calculated with a model with 
influential BQL, are biased because the influence of the BQL values is not 
accounted for. (if a certain prediction for a measurable concentration is 
changed by 10% because of the M3 method, that will turn up as a similar bias in 
CWRES). The NPDEs as referenced to in the above discussion (Nguyen2012 JPKPD 
0.1007/s10928-012-9264-2) do not suffer from that drawback as one can see the 
complete profile (cf Fig 8 of Nguyen2012).

Hope this helps,

Jeroen

http://pd-value.com

jer...@pd-value.com<mailto:jer...@pd-value.com>

@PD_value

+31 6 23118438

-- More value out of your data!

On 2/9/20 2:32 am, Bill Denney wrote:

Hi Mutaz,



Matt Hutmac

Re: [NMusers] M3 method - WRES, and CWRES

2020-09-05 Thread Matthew Fidler
Thank you Bob,

The NPDE 2.0 manual discusses the methods that NPDE uses to handle BLQ,
including replacing values with pred, ipred, or lloq, or simulating from a
uniform random value while calculating the NPDE (cdf method).  The NONMEM
manual doesn't mention the method used.  My guess is the cdf method.

I realize that no one has answered Mu'taz's question.

As far as if the CWRES is appropriate for BLQ data, the CWRES method uses
the FOCEi approximation to calculate residuals.  However with M3/M4 and
other methods the likelihood for these points is not the FOCEi objective
function but the M3/M4 likelihood so anything you do here with CWRES
doesn't follow or add to the likelihood observed during minimization.
Therefore in my opinion, there will be bias of some sort here.


Best Regards,

Matt.

On Thu, Sep 3, 2020 at 3:06 PM Bauer, Robert 
wrote:

> Matt:
>
> The NPDE and NPD systems in NONMEM are described in the nm744.pdf manual (
> https://nonmem.iconplc.com/nonmem744 ), pages 70-75, and follow along the
> work of Comet, Brendel, Ngyuen, Mentre, etc.  The NPDE R package is not
> used within NONMEM.
>
>
>
>
>
> Robert J. Bauer, Ph.D.
>
> Senior Director
>
> Pharmacometrics R
>
> ICON Early Phase
>
> 820 W. Diamond Avenue
>
> Suite 100
>
> Gaithersburg, MD 20878
>
> Office: (215) 616-6428
>
> Mobile: (925) 286-0769
>
> robert.ba...@iconplc.com
>
> www.iconplc.com
>
>
>
> *From:* owner-nmus...@globomaxnm.com  *On
> Behalf Of *Matthew Fidler
> *Sent:* Thursday, September 3, 2020 6:08 AM
> *To:* Jeroen Elassaiss-Schaap (PD-value B.V.) 
> *Cc:* Bill Denney ; Mu'taz Jaber <
> jaber...@umn.edu>; nmusers@globomaxnm.com
> *Subject:* Re: [NMusers] M3 method - WRES, and CWRES
>
>
>
> Hi everyone,
>
>
>
> As an aside, nlmixr's upcoming release (that supports censoring) simulates
> a value using a truncated normal based on the ipred, variance at that point
> and the censoring column to produce an observation.  This observation is
> used to calculate RES, WRES, CWRES.  It is flagged so you can see which
> values use this approach.  In theory, since this is simulated from the
> IPRED/truncated the CWRES would be likely follow the distribution closer.
>
>
>
> I'm unsure if the new NONMEM uses this approach.
>
>
>
> Another question from my end is the NPDE:  There are many methods to
> handle BLQ values with NPDE R package, does anyone know which NONMEM uses?
> Or do you need to use the NPDE package to get these values from NONMEM?
>
>
>
> Matt.
>
>
>
>
>
>
>
> On Wed, Sep 2, 2020 at 2:09 AM Jeroen Elassaiss-Schaap (PD-value B.V.) <
> jer...@pd-value.com> wrote:
>
> Hi Mutaz, Bill,
>
> It might be useful to use NPDEs, as discussed in
> https://www.cognigen.com/nmusers/2019-February/7376.html;  the whole
> thread is worthwhile reading. NPDEs can be calculated also for BQL values.
>
> Bill -thanks for pointing to excellent post of Matt! I would take as most
> important point that CWRES for non-BQL values, calculated with a model with
> influential BQL, are biased because the influence of the BQL values is not
> accounted for. (if a certain prediction for a measurable concentration is
> changed by 10% because of the M3 method, that will turn up as a similar
> bias in CWRES). The NPDEs as referenced to in the above discussion
> (Nguyen2012 JPKPD 0.1007/s10928-012-9264-2) do not suffer from that
> drawback as one can see the complete profile (cf Fig 8 of Nguyen2012).
>
> Hope this helps,
>
> Jeroen
>
> http://pd-value.com
>
> jer...@pd-value.com
>
> @PD_value
>
> +31 6 23118438
>
> -- More value out of your data!
>
> On 2/9/20 2:32 am, Bill Denney wrote:
>
> Hi Mutaz,
>
>
>
> Matt Hutmacher described it well here:
> https://www.cognigen.com/nmusers/2010-April/2448.html
>
>
>
> A very brief summary of his excellent post is that subjects with a
> combination of censored (BLQ) an uncensored (above the LLOQ and below the
> ULOQ) will be biased in their reporting of CWRES because you cannot
> calculate CWRES for BLQ values.  (I say this before looking up what MDVRES
> does.)
>
>
>
> My guess that Bob or someone else can confirm is that the bias is
> anticipated to be relatively small compared to the value of being able to
> compare CWRES values the other observations for a subject.  It does not
> definitively mean that the results are unbiased (see Matt’s Tmax example),
> but generally, the CWRES values previously omitted are more useful than
> excluding them from calculation.
>
>
>
> Thanks,
>
>
>
> Bill
>
>
>
> *From:* owner-nmus...@globomaxnm.com  *On
> Behalf Of *Mu't

RE: [NMusers] M3 method - WRES, and CWRES

2020-09-03 Thread Bauer, Robert
Matt:
The NPDE and NPD systems in NONMEM are described in the nm744.pdf manual ( 
https://nonmem.iconplc.com/nonmem744 ), pages 70-75, and follow along the work 
of Comet, Brendel, Ngyuen, Mentre, etc.  The NPDE R package is not used within 
NONMEM.


Robert J. Bauer, Ph.D.
Senior Director
Pharmacometrics R
ICON Early Phase
820 W. Diamond Avenue
Suite 100
Gaithersburg, MD 20878
Office: (215) 616-6428
Mobile: (925) 286-0769
robert.ba...@iconplc.com<mailto:robert.ba...@iconplc.com>
www.iconplc.com<http://www.iconplc.com>

From: owner-nmus...@globomaxnm.com  On Behalf Of 
Matthew Fidler
Sent: Thursday, September 3, 2020 6:08 AM
To: Jeroen Elassaiss-Schaap (PD-value B.V.) 
Cc: Bill Denney ; Mu'taz Jaber 
; nmusers@globomaxnm.com
Subject: Re: [NMusers] M3 method - WRES, and CWRES

Hi everyone,

As an aside, nlmixr's upcoming release (that supports censoring) simulates a 
value using a truncated normal based on the ipred, variance at that point and 
the censoring column to produce an observation.  This observation is used to 
calculate RES, WRES, CWRES.  It is flagged so you can see which values use this 
approach.  In theory, since this is simulated from the IPRED/truncated the 
CWRES would be likely follow the distribution closer.

I'm unsure if the new NONMEM uses this approach.

Another question from my end is the NPDE:  There are many methods to handle BLQ 
values with NPDE R package, does anyone know which NONMEM uses?  Or do you need 
to use the NPDE package to get these values from NONMEM?

Matt.



On Wed, Sep 2, 2020 at 2:09 AM Jeroen Elassaiss-Schaap (PD-value B.V.) 
mailto:jer...@pd-value.com>> wrote:

Hi Mutaz, Bill,

It might be useful to use NPDEs, as discussed in 
https://www.cognigen.com/nmusers/2019-February/7376.html<https://www.cognigen.com/nmusers/2019-February/7376.html>;
  the whole thread is worthwhile reading. NPDEs can be calculated also for BQL 
values.

Bill -thanks for pointing to excellent post of Matt! I would take as most 
important point that CWRES for non-BQL values, calculated with a model with 
influential BQL, are biased because the influence of the BQL values is not 
accounted for. (if a certain prediction for a measurable concentration is 
changed by 10% because of the M3 method, that will turn up as a similar bias in 
CWRES). The NPDEs as referenced to in the above discussion (Nguyen2012 JPKPD 
0.1007/s10928-012-9264-2) do not suffer from that drawback as one can see the 
complete profile (cf Fig 8 of Nguyen2012).

Hope this helps,

Jeroen

http://pd-value.com<http://pd-value.com>

jer...@pd-value.com<mailto:jer...@pd-value.com>

@PD_value

+31 6 23118438

-- More value out of your data!
On 2/9/20 2:32 am, Bill Denney wrote:
Hi Mutaz,

Matt Hutmacher described it well here: 
https://www.cognigen.com/nmusers/2010-April/2448.html<https://www.cognigen.com/nmusers/2010-April/2448.html>

A very brief summary of his excellent post is that subjects with a combination 
of censored (BLQ) an uncensored (above the LLOQ and below the ULOQ) will be 
biased in their reporting of CWRES because you cannot calculate CWRES for BLQ 
values.  (I say this before looking up what MDVRES does.)

My guess that Bob or someone else can confirm is that the bias is anticipated 
to be relatively small compared to the value of being able to compare CWRES 
values the other observations for a subject.  It does not definitively mean 
that the results are unbiased (see Matt’s Tmax example), but generally, the 
CWRES values previously omitted are more useful than excluding them from 
calculation.

Thanks,

Bill

From: owner-nmus...@globomaxnm.com<mailto:owner-nmus...@globomaxnm.com> 
mailto:owner-nmus...@globomaxnm.com>> On Behalf 
Of Mu'taz Jaber
Sent: Tuesday, September 1, 2020 7:25 PM
To: nmusers@globomaxnm.com<mailto:nmusers@globomaxnm.com>
Subject: [NMusers] M3 method - WRES, and CWRES

All,

Back in April 2010, Sebastian Bihorel and Martin Bergstrand initiated a 
discussion regarding using the M3 and M4 methods for handling BQL data and how 
it seemed to be a bug that NONMEM wouldn't compute WRES for the entire set of 
subject data records whenever a BQL was included 
(https://www.cognigen.com/nmusers/2010-April/2445.html<https://www.cognigen.com/nmusers/2010-April/2445.html>).
  Tom Ludden responded with the following post 
(https://www.cognigen.com/nmusers/2010-April/2447.html<https://www.cognigen.com/nmusers/2010-April/2447.html>):

This issue was discussed with Stuart Beal. He believed that weighted
residuals would be incorrect for an individual that had both continuous
dependent variables and a likelihood in the calculation of their
contribution to the objective function value, as is the case with his M3
or M4 BQL methods The code for both RES and WRES are intentionally
bypassed in these cases.

Since then, we now have easy functionality with the F_FLAG=1 condition of the 
M3/M4 code in $ERROR to tack on MDVRES=1 that allows 

Re: [NMusers] M3 method - WRES, and CWRES

2020-09-03 Thread Matthew Fidler
Hi everyone,

As an aside, nlmixr's upcoming release (that supports censoring) simulates
a value using a truncated normal based on the ipred, variance at that point
and the censoring column to produce an observation.  This observation is
used to calculate RES, WRES, CWRES.  It is flagged so you can see which
values use this approach.  In theory, since this is simulated from the
IPRED/truncated the CWRES would be likely follow the distribution closer.

I'm unsure if the new NONMEM uses this approach.

Another question from my end is the NPDE:  There are many methods to handle
BLQ values with NPDE R package, does anyone know which NONMEM uses?  Or do
you need to use the NPDE package to get these values from NONMEM?

Matt.



On Wed, Sep 2, 2020 at 2:09 AM Jeroen Elassaiss-Schaap (PD-value B.V.) <
jer...@pd-value.com> wrote:

> Hi Mutaz, Bill,
>
> It might be useful to use NPDEs, as discussed in
> https://www.cognigen.com/nmusers/2019-February/7376.html;  the whole
> thread is worthwhile reading. NPDEs can be calculated also for BQL values.
>
> Bill -thanks for pointing to excellent post of Matt! I would take as most
> important point that CWRES for non-BQL values, calculated with a model with
> influential BQL, are biased because the influence of the BQL values is not
> accounted for. (if a certain prediction for a measurable concentration is
> changed by 10% because of the M3 method, that will turn up as a similar
> bias in CWRES). The NPDEs as referenced to in the above discussion
> (Nguyen2012 JPKPD 0.1007/s10928-012-9264-2) do not suffer from that
> drawback as one can see the complete profile (cf Fig 8 of Nguyen2012).
>
> Hope this helps,
>
> Jeroen
>
> http://pd-value.comjer...@pd-value.com
> @PD_value
> +31 6 23118438
> -- More value out of your data!
>
> On 2/9/20 2:32 am, Bill Denney wrote:
>
> Hi Mutaz,
>
>
>
> Matt Hutmacher described it well here:
> https://www.cognigen.com/nmusers/2010-April/2448.html
>
>
>
> A very brief summary of his excellent post is that subjects with a
> combination of censored (BLQ) an uncensored (above the LLOQ and below the
> ULOQ) will be biased in their reporting of CWRES because you cannot
> calculate CWRES for BLQ values.  (I say this before looking up what MDVRES
> does.)
>
>
>
> My guess that Bob or someone else can confirm is that the bias is
> anticipated to be relatively small compared to the value of being able to
> compare CWRES values the other observations for a subject.  It does not
> definitively mean that the results are unbiased (see Matt’s Tmax example),
> but generally, the CWRES values previously omitted are more useful than
> excluding them from calculation.
>
>
>
> Thanks,
>
>
>
> Bill
>
>
>
> *From:* owner-nmus...@globomaxnm.com  *On
> Behalf Of *Mu'taz Jaber
> *Sent:* Tuesday, September 1, 2020 7:25 PM
> *To:* nmusers@globomaxnm.com
> *Subject:* [NMusers] M3 method - WRES, and CWRES
>
>
>
> All,
>
>
>
> Back in April 2010, Sebastian Bihorel and Martin Bergstrand initiated a
> discussion regarding using the M3 and M4 methods for handling BQL data and
> how it seemed to be a bug that NONMEM wouldn't compute WRES for the entire
> set of subject data records whenever a BQL was included (
> https://www.cognigen.com/nmusers/2010-April/2445.html).  Tom Ludden
> responded with the following post (
> https://www.cognigen.com/nmusers/2010-April/2447.html):
>
>
>
> This issue was discussed with Stuart Beal. He believed that weighted
>
> residuals would be incorrect for an individual that had both continuous
>
> dependent variables and a likelihood in the calculation of their
>
> contribution to the objective function value, as is the case with his M3
>
> or M4 BQL methods The code for both RES and WRES are intentionally
>
> bypassed in these cases.
>
>
>
> Since then, we now have easy functionality with the F_FLAG=1 condition of
> the M3/M4 code in $ERROR to tack on MDVRES=1 that allows the calculation of
> WRES and CWRES to be available in output tables.
>
>
>
> My questions are: Is Stuart Beal's original concern still valid?  Do these
> NONMEM updates give us appropriate WRES and CWRES for plotting purposes for
> individuals whose records contain BQL data?
>
>
>
> Thank you,
>
>
>
> Mutaz Jaber
>
> PhD student
>
> University of Minnesota
>
>
>
> ---
>
> *Mutaz M. Jaber, PharmD.*
>
> PhD student, Pharmacometrics
>
> Experimental and Clinical Pharmacology
>
> University of Minnesota
>
> 717 Delaware St SE; Room 468
>
> Minneapolis, MN 55414
>
> Email: jaber...@umn.edu
>
> Phone: +1 651-706-5202
>
>
>
> *~ Stay curious*
>
>


Re: [NMusers] M3 method - WRES, and CWRES

2020-09-02 Thread Jeroen Elassaiss-Schaap (PD-value B.V.)

Hi Mutaz, Bill,

It might be useful to use NPDEs, as discussed in 
https://www.cognigen.com/nmusers/2019-February/7376.html;  the whole 
thread is worthwhile reading. NPDEs can be calculated also for BQL values.


Bill -thanks for pointing to excellent post of Matt! I would take as 
most important point that CWRES for non-BQL values, calculated with a 
model with influential BQL, are biased because the influence of the BQL 
values is not accounted for. (if a certain prediction for a measurable 
concentration is changed by 10% because of the M3 method, that will turn 
up as a similar bias in CWRES). The NPDEs as referenced to in the above 
discussion (Nguyen2012 JPKPD 0.1007/s10928-012-9264-2) do not suffer 
from that drawback as one can see the complete profile (cf Fig 8 of 
Nguyen2012).


Hope this helps,

Jeroen

http://pd-value.com
jer...@pd-value.com
@PD_value
+31 6 23118438
-- More value out of your data!

On 2/9/20 2:32 am, Bill Denney wrote:


Hi Mutaz,

Matt Hutmacher described it well here: 
https://www.cognigen.com/nmusers/2010-April/2448.html


A very brief summary of his excellent post is that subjects with a 
combination of censored (BLQ) an uncensored (above the LLOQ and below 
the ULOQ) will be biased in their reporting of CWRES because you 
cannot calculate CWRES for BLQ values.  (I say this before looking up 
what MDVRES does.)


My guess that Bob or someone else can confirm is that the bias is 
anticipated to be relatively small compared to the value of being able 
to compare CWRES values the other observations for a subject.  It does 
not definitively mean that the results are unbiased (see Matt’s Tmax 
example), but generally, the CWRES values previously omitted are more 
useful than excluding them from calculation.


Thanks,

Bill

*From:* owner-nmus...@globomaxnm.com 
<mailto:owner-nmus...@globomaxnm.com> <mailto:owner-nmus...@globomaxnm.com>> *On Behalf Of *Mu'taz Jaber

*Sent:* Tuesday, September 1, 2020 7:25 PM
*To:* nmusers@globomaxnm.com <mailto:nmusers@globomaxnm.com>
*Subject:* [NMusers] M3 method - WRES, and CWRES

All,

Back in April 2010, Sebastian Bihorel and Martin Bergstrand initiated 
a discussion regarding using the M3 and M4 methods for handling BQL 
data and how it seemed to be a bug that NONMEM wouldn't compute WRES 
for the entire set of subject data records whenever a BQL was included 
(https://www.cognigen.com/nmusers/2010-April/2445.html). Tom Ludden 
responded with the following post 
(https://www.cognigen.com/nmusers/2010-April/2447.html):


This issue was discussed with Stuart Beal. He believed that weighted

residuals would be incorrect for an individual that had both
continuous

dependent variables and a likelihood in the calculation of their

contribution to the objective function value, as is the case with
his M3

or M4 BQL methods The code for both RES and WRES are intentionally

bypassed in these cases.

Since then, we now have easy functionality with the F_FLAG=1 condition 
of the M3/M4 code in $ERROR to tack on MDVRES=1 that allows the 
calculation of WRES and CWRES to be available in output tables.


My questions are: Is Stuart Beal's original concern still valid?  Do 
these NONMEM updates give us appropriate WRES and CWRES for plotting 
purposes for individuals whose records contain BQL data?


Thank you,

Mutaz Jaber

PhD student

University of Minnesota

---

*Mutaz M. Jaber, PharmD.*

PhD student, Pharmacometrics

Experimental and Clinical Pharmacology

University of Minnesota

717 Delaware St SE; Room 468

Minneapolis, MN 55414

Email: jaber...@umn.edu <mailto:jaber...@umn.edu>

Phone: +1 651-706-5202

*~ Stay curious*



RE: [NMusers] M3 method - WRES, and CWRES

2020-09-01 Thread Bill Denney
Hi Mutaz,



Matt Hutmacher described it well here:
https://www.cognigen.com/nmusers/2010-April/2448.html



A very brief summary of his excellent post is that subjects with a
combination of censored (BLQ) an uncensored (above the LLOQ and below the
ULOQ) will be biased in their reporting of CWRES because you cannot
calculate CWRES for BLQ values.  (I say this before looking up what MDVRES
does.)



My guess that Bob or someone else can confirm is that the bias is
anticipated to be relatively small compared to the value of being able to
compare CWRES values the other observations for a subject.  It does not
definitively mean that the results are unbiased (see Matt’s Tmax example),
but generally, the CWRES values previously omitted are more useful than
excluding them from calculation.



Thanks,



Bill



*From:* owner-nmus...@globomaxnm.com  *On
Behalf Of *Mu'taz Jaber
*Sent:* Tuesday, September 1, 2020 7:25 PM
*To:* nmusers@globomaxnm.com
*Subject:* [NMusers] M3 method - WRES, and CWRES



All,



Back in April 2010, Sebastian Bihorel and Martin Bergstrand initiated a
discussion regarding using the M3 and M4 methods for handling BQL data and
how it seemed to be a bug that NONMEM wouldn't compute WRES for the entire
set of subject data records whenever a BQL was included (
https://www.cognigen.com/nmusers/2010-April/2445.html).  Tom Ludden
responded with the following post (
https://www.cognigen.com/nmusers/2010-April/2447.html):



This issue was discussed with Stuart Beal. He believed that weighted

residuals would be incorrect for an individual that had both continuous

dependent variables and a likelihood in the calculation of their

contribution to the objective function value, as is the case with his M3

or M4 BQL methods The code for both RES and WRES are intentionally

bypassed in these cases.



Since then, we now have easy functionality with the F_FLAG=1 condition of
the M3/M4 code in $ERROR to tack on MDVRES=1 that allows the calculation of
WRES and CWRES to be available in output tables.



My questions are: Is Stuart Beal's original concern still valid?  Do these
NONMEM updates give us appropriate WRES and CWRES for plotting purposes for
individuals whose records contain BQL data?



Thank you,



Mutaz Jaber

PhD student

University of Minnesota



---

*Mutaz M. Jaber, PharmD.*

PhD student, Pharmacometrics

Experimental and Clinical Pharmacology

University of Minnesota

717 Delaware St SE; Room 468

Minneapolis, MN 55414

Email: jaber...@umn.edu

Phone: +1 651-706-5202



*~ Stay curious*


[NMusers] M3 method - WRES, and CWRES

2020-09-01 Thread Mu'taz Jaber
All,

Back in April 2010, Sebastian Bihorel and Martin Bergstrand initiated a
discussion regarding using the M3 and M4 methods for handling BQL data and
how it seemed to be a bug that NONMEM wouldn't compute WRES for the entire
set of subject data records whenever a BQL was included (
https://www.cognigen.com/nmusers/2010-April/2445.html).  Tom Ludden
responded with the following post (
https://www.cognigen.com/nmusers/2010-April/2447.html):

This issue was discussed with Stuart Beal. He believed that weighted
residuals would be incorrect for an individual that had both continuous
dependent variables and a likelihood in the calculation of their
contribution to the objective function value, as is the case with his M3
or M4 BQL methods The code for both RES and WRES are intentionally
bypassed in these cases.


Since then, we now have easy functionality with the F_FLAG=1 condition of
the M3/M4 code in $ERROR to tack on MDVRES=1 that allows the calculation of
WRES and CWRES to be available in output tables.

My questions are: Is Stuart Beal's original concern still valid?  Do these
NONMEM updates give us appropriate WRES and CWRES for plotting purposes for
individuals whose records contain BQL data?

Thank you,

Mutaz Jaber
PhD student
University of Minnesota

---
*Mutaz M. Jaber, PharmD.*
PhD student, Pharmacometrics
Experimental and Clinical Pharmacology
University of Minnesota
717 Delaware St SE; Room 468
Minneapolis, MN 55414
Email: jaber...@umn.edu
Phone: +1 651-706-5202

*~ Stay curious*