Re: [R] WHO Anthro growth curve macros and R

2009-12-28 Thread Thomas Lumley
On Mon, 28 Dec 2009, 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/so

Re: [R] WHO Anthro growth curve macros and R

2009-12-28 Thread 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 wei

[R] WHO Anthro growth curve macros and R

2009-12-28 Thread Gustaf Rydevik
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 n