Hi Pyry + Martin + NMusers,
I wanted to make 2 comments on this discussion. Pyry wrote:
With reference to Martin saying that “A greater problem with these plots is the
commonly held expectation that for a "good model" a smooth or regression line
should align with the line of unity. Though this
:16 AM
To: Gobburu, Joga
mailto:jgobb...@rx.umaryland.edu>>,
nmusers@globomaxnm.com<mailto:nmusers@globomaxnm.com>
mailto:nmusers@globomaxnm.com>>
Subject: Re: [NMusers] Observed (yaxis) vs Predicted (xaxis) Diagnostic Plot -
Scientific basis.
You don't often get email from
Dear Martin and NMusers,
With reference to Martin saying that “A greater problem with these plots is
the commonly held expectation that for a "good model" a smooth or
regression line should align with the line of unity. Though this seems
intuitive it is a flawed assumption”, I would like to
B, FRACP
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> mobile:NZ+64(21)46 23 53 ; FR+33(6)62 32 46 72
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> email: n.holf...@auckland.ac.nz
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> web: http://holford.fmhs.auckland.ac.nz/
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> *From:* owner-nmus...@globomaxnm.com
> *On Behalf Of *Martin Bergstrand
> *Sent:* Friday, August 18, 2023 9:48 AM
&g
Cc:* nmusers@globomaxnm.com
*Subject:* Re: [NMusers] Observed (yaxis) vs Predicted (xaxis)
Diagnostic Plot - Scientific basis.
Dear Joga and all,
Joga makes a valuable point that all pharmacometricians should be
aware of. Standard methodology for regression assumes that the
x-variable is without
, 2023 at 4:52 AM
To: NMusers
Subject: Fwd: [NMusers] Observed (yaxis) vs Predicted (xaxis) Diagnostic Plot -
Scientific basis.
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Hi Nick,
I hope you are well! I
f Of *Martin Bergstrand
*Sent:* Friday, August 18, 2023 9:48 AM
*To:* Gobburu, Joga
*Cc:* nmusers@globomaxnm.com
*Subject:* Re: [NMusers] Observed (yaxis) vs Predicted (xaxis)
Diagnostic Plot - Scientific basis.
Dear Joga and all,
Joga makes a valuable point that all pharmacometricians shou
e is fitting noise in
the wrong direction if the observed is actually on the x-axis”.
Thank you…J
*From: *James G Wright
*Date: *Thursday, August 17, 2023 at 7:16 AM
*To: *Gobburu, Joga ,
nmusers@globomaxnm.com
*Subject: *Re: [NMusers] Observed (yaxis) vs Pred
.nz>
web: http://holford.fmhs.auckland.ac.nz/<http://holford.fmhs.auckland.ac.nz/>
From: owner-nmus...@globomaxnm.com On Behalf Of
Martin Bergstrand
Sent: Friday, August 18, 2023 9:48 AM
To: Gobburu, Joga
Cc: nmusers@globomaxnm.com
Subject: Re: [NMusers] Observed (yaxis) vs Pred
Dear Joga and all,
Joga makes a valuable point that all pharmacometricians should be aware of.
Standard methodology for regression assumes that the x-variable is without
error (loess, linear regression etc.). Note that it is the same for NLME
models i.e. we generally assume that our independent
served is actually on the x-axis”. Thank you…J
>
>
>
> *From: *James G Wright
> *Date: *Thursday, August 17, 2023 at 7:16 AM
> *To: *Gobburu, Joga , nmusers@globomaxnm.com <
> nmusers@globomaxnm.com>
> *Subject: *Re: [NMusers] Observed (yaxis) vs Predicted (xaxis) Diag
at 7:16 AM
To: Gobburu, Joga , nmusers@globomaxnm.com
Subject: Re: [NMusers] Observed (yaxis) vs Predicted (xaxis) Diagnostic Plot -
Scientific basis.
You don't often get email from ja...@wright-dose.com. Learn why this is
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C
So whichever axis the observed data is plotted on is parallel to the
direction of noise (random residual error). When you fit the loess
line, I think it will generally assume noise is vertical i.e. parallel
to the y-axis. So the problem is really that the loess line is fitting
noise in the
Dear Friends – Observations versus population predicted is considered a
standard diagnostic plot in our field. I used to place observations on the
x-axis and predictions on the yaxis. Then I was pointed to a publication from
ISOP
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