Hi,
I've seen this topic has been up before, but can't fix my issue through reading that earlier thread.
I'm trying to BOXCOX transform a couple of variables which are all pretty similar (no negative values, approx same amount of missing values, etc). Some of the variables get transformed, but some just turn all the cells empty. I'm not specifying the lamda, just using BOXCOX (variable). Anyone understanding why it works for some variables but not all of them?
Best,
Elvira
BOXCOX transformation, empty cells for some variables
Re: BOXCOX transformation, empty cells for some variables
attach a data set?
jonathon
jonathon
Re: BOXCOX transformation, empty cells for some variables
Attached it! Thank you so much for your help.
Re: BOXCOX transformation, empty cells for some variables
hi,
sorry for the delay. i think these columns result in negative lambda values, for which boxcox is undefined.
jonathon
sorry for the delay. i think these columns result in negative lambda values, for which boxcox is undefined.
jonathon
Re: BOXCOX transformation, empty cells for some variables
No worries. Thanks for getting back, that makes sense.
Elvira
Elvira

 Posts: 4
 Joined: Fri Jun 18, 2021 9:16 pm
Re: BOXCOX transformation, empty cells for some variables
Following up on this earlier thread, I believe that this is an error in the Jamovi implementation. The BoxCox transformation is undefined for negative data, but negative lambda values are allowed (lambda=1 is an inverse transformation, etc.) and boxcox() in R has no problem with negative lambdas.
A user workaround is to create a new transformation using the BoxCox formula:
($source^VBOXCOXLAMBDA($source)1)/VBOXCOXLAMBDA($source)
This gives the same result as BOXCOX for positive lambdas, but also works for negative lambdas.
This appears to be a bug, it would be great if this could be addressed in a future update.
A user workaround is to create a new transformation using the BoxCox formula:
($source^VBOXCOXLAMBDA($source)1)/VBOXCOXLAMBDA($source)
This gives the same result as BOXCOX for positive lambdas, but also works for negative lambdas.
This appears to be a bug, it would be great if this could be addressed in a future update.
Re: BOXCOX transformation, empty cells for some variables
does this look like an appropriate fix?
https://github.com/jamovi/jamovi/pull/1341/files
with thanks
https://github.com/jamovi/jamovi/pull/1341/files
with thanks
Re: BOXCOX transformation, empty cells for some variables
Hi! I'm experiencing the same problem where BOXCOX turns up empty for my variables. I've tried the alternative workaround posted above but it still doesn't work, the results are still blank. Any way to fix this? Thanks!
Re: BOXCOX transformation, empty cells for some variables
Hi! how can i add this link/file and run it on jamovi?jonathon wrote: ↑Wed Apr 26, 2023 6:27 am does this look like an appropriate fix?
https://github.com/jamovi/jamovi/pull/1341/files
with thanks
Re: BOXCOX transformation, empty cells for some variables
this has been incorporated into the latest versions of jamovi.
jonathon
jonathon