Additive error being bound to minimize the effect of the BLQ imputation
#1
Posted 16 June 2022 - 10:43 PM
#2
Posted 16 June 2022 - 11:19 PM
Hi David,
Thanks for contacting Certara. In regards to your question, I am not sure which publication you are referring to.
I have attached a link (Presentation on handling LLOQ) that may be of use to you.
https://www.youtube....h?v=xX-yCO5Rzag
Thanks and regards
Chnadramouli
#3
Posted 17 June 2022 - 03:08 AM
Attached Files
#4
Posted 05 July 2022 - 05:43 AM
Hi David,
Apologies thought I had answered your question. With Phoenix you will be using the M3 method as mentioned in the link below
Thanks
Mouli
https://www.youtube....h?v=xX-yCO5Rzag
#5
Posted 05 July 2022 - 10:51 AM
The model seems somewhat complex but this can be done in Phoenix too.
AddErr and PropErr are the fixed effects and they are combined into W which is used as a coefficient for the sigma.
That could be used in PML too (create fixefs AddErr and PropErr and use them to build W).
Since AddErr has a low limit as 0.00626, I assume it is the constraint you/the authors are talking about.
Prop=C*PropErr
Add=AddErr
W= sqrt(Add^2 + Prop^2))
error(CEps = 1)
observe(CObs = C + W*CEps)
fixef(AddErr = c(0.0138181,0.00626,))
fixef(PropErr = c(,0.171622,))
Edited by Simon Davis, 05 July 2022 - 11:39 AM.
#6
Posted 06 July 2022 - 07:42 PM
Hi David,
Apologies thought I had answered your question. With Phoenix you will be using the M3 method as mentioned in the link below
Thanks
Mouli
Thanks Mouli for your explanation.
#7
Posted 06 July 2022 - 07:44 PM
The model seems somewhat complex but this can be done in Phoenix too.
AddErr and PropErr are the fixed effects and they are combined into W which is used as a coefficient for the sigma.
That could be used in PML too (create fixefs AddErr and PropErr and use them to build W).
Since AddErr has a low limit as 0.00626, I assume it is the constraint you/the authors are talking about.
Prop=C*PropErr
Add=AddErr
W= sqrt(Add^2 + Prop^2))
error(CEps = 1)
observe(CObs = C + W*CEps)
fixef(AddErr = c(0.0138181,0.00626,))
fixef(PropErr = c(,0.171622,))
Thanks, Simon, for providing me with text codes for PML, this is really helpful!
Best
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