[R] WHO Anthro growth curve macros and R

[Frank E Harrell Jr]

Gustaf,

I would be advisable to first check that such z scores are valid 
statistically (I have my doubts).  They make a number of assumptions, 
chief among them being that un-normalized weight is not a proper 
physiologic summary.  It is almost always the case that joint modeling 
of age and weight (e.g., ANCOVA) works better.

Frank

Gustaf Rydevik wrote:
> Hi all,
> 
> I've got a project where I have to calculate weight-for-age Z-scores,
> preferably using the WHO standards.
> 
> WHO have been very nice to publish macros for doing this in both
> STATA,SPSS, SAS and Splus formats
> (see http://www.who.int/childgrowth/software/en/), but for some reason
> have chosen not to use the free R alternative to Splus.
> 
> In the Splus zipfile there are nine datafiles with a "sdd" file
> ending, presumably data dumps from Splus 7.x. I've tried using
> restore.data from the foreign package, but that does not work
> (probably because the data is saved in the newer format).
> 
> I'm considering trying to read in spss files and massaging them to fit
> to the format that the splus macro is expecting, but I'd prefer to be
> able to use the Splus files directly.
> 
> Has anyone on the list tried using the WHO anthro macros with R, and
> can tell me how they did it?
> Alternatively, could some, very kind, person try and open the Splus
> files, and save them in a R-readable format?
> I would be extremely grateful for any help on this.
> 
> Best regards,
> 
> Gustaf Rydevik
> 
> 


-- 
Frank E Harrell Jr   Professor and Chairman        School of Medicine
                      Department of Biostatistics   Vanderbilt University