jamovi

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

attach a data set?

jonathon

Attached it! Thank you so much for your help.

hi,

sorry for the delay. i think these columns result in negative lambda values, for which boxcox is undefined.

jonathon

No worries. Thanks for getting back, that makes sense.

Elvira

Following up on this earlier thread, I believe that this is an error in the Jamovi implementation. The Box-Cox 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 Box-Cox 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.

does this look like an appropriate fix?

https://github.com/jamovi/jamovi/pull/1341/files

with thanks

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!

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

Hi! how can i add this link/file and run it on jamovi?

this has been incorporated into the latest versions of jamovi.

jonathon