Consistant test for NAs in a factor when exclude = NULL?
On Oct 27, 2011, at 12:21 AM, andrewH wrote:
Thanks Jeff! I appreciate you sharing your experience. My data set is survey data, 13,209 records over nine years, collected by someone else, converted from SPSS format. It includes missing values, identified however SPSS does so, and translated to NAs by the import process. It also includes values along the lines of "none of your business" or "beats me" that are missing so far as I am concerned. I have assigned NAs to these values. Now I am trying to figure out some things about where these missing values are -- whether they are disproportionately located in any period or group. I have been trying to get counts for subsets, but I have not been able to make the subset counts add up to the total counts that I get from, e.g. summary. So I wrote these simplified versions, and even for the simplest examples, I could not find a function that correctly identified the NAs that I knew were there because I put them there myself. That is why I am looking for help. Does this make sense?
You might consider looking at the Hmisc package. I think it provides
facilities for multiple missing attributes imported from SAS datasets.
The help page to consult is sas.get {Hmisc}, I see no indication that
a direct spss read facility was contmeplated, so it may take some
extra work to get use out of this application of R attributes to store
type-of-missingness-information in sequence with R NA's.
David Winsemius, MD West Hartford, CT