I have two versions of SPSS at work. SPSS 11 running on Windows XP and SPSS 20 running on Linux. Both copies of SPSS work fine. Files created with either version of SPSS open without incident on the other version of SPSS. I.E. - I can create a .sav file with SPSS 20 on Linux and open it on SPSS 11 on Windows without incident.
But, if I create a .sav file with SPSS 20 and import the data into either R or PSPP (on Linux), I get a bunch of warnings. The data appears to import correctly, but I am concerned by the warnings. I do not see any warning when importing a .sav from SPSS 11 or other .sav files I have been sent. Many of the analysts at my company use SPSS so I've gotten SPSS files from different versions of SPSS and I have never before seen this warning. The warning messages are nearly identical between PSPP and R which makes sense. AFAIK, they use the same underlying libs to import the data. This is the R error:
Warning messages:
1: In read.spss("test.sav") :
test.sav: File-indicated value is different from internal value for at least one of the three system values. SYSMIS: indicated -1.79769e+308, expected -1.79769e+308; HIGHEST: 1.79769e+308, 1.79769e+308; LOWEST: -1.79769e+308, -1.79769e+308
2: In read.spss("test.sav") :
test.sav: Unrecognized record type 7, subtype 18 encountered in system file
The .sav file is really simple. It has two columns, dumb and dumber. Both are integers. The first two contains two values of 1.0. The second row contains two values of 2.0. I can provide the file on request (I don't see any way to upload it to SO). If anyone would like to see the actual file, PM me and I'll send it to you.
dumb dumber
1.0 1.0
2.0 2.0
Thoughts? Anyone know the best way to file a bug against R without getting roasted alive on the mailing list? :-)
EDIT: I used the term "Error" in the title line. I'll leave it, but I should not have used this word. The comments below are correct in pointing out that the messages I am seeing are warnings, not errors. I do however feel that this is made clear in the body of the question above. Clearly, the SPSS data format has changed over time and SPSS/IBM have failed to document these changes which is the root of the problem.
Answer
It's not an error message. It is only a warning. SPSS refuses to document their file formats so people have not been motivated to track down by reverse engineering the structure of new "subtypes". There is no way to file a bug report without getting roasted because there is no bug .... other than a closed format and that bug complaint should be filed with the owners of SPSS!
EDIT: The R-Core is a volunteer group and takes it responsibilities very seriously. It exerts major efforts to track down anything that affects the stability of systems or produces erroneous calculations. If you were willing to be a bit more respectful of the authors of R and suggest the possibility of collaboration on the R-devel mailing list to identify solutions to this problem without using the term "bug", you would arouse much less hostility. There might be someone who would be willing to see if a simple .sav file such as the one you constructed could be examined under a hexadecimal microscope to identify whatever infinite negative value is being mistaken for another infinite negative value. Most of the R-Core is not in possession of working copies of SPSS.
You could offer this link as an example of the product of others who have attempted the reverse engineering of SPSS .sav formats:
Edit: 4/2015; I have seen a recent addition to the ?read.spss help file that refers one to pkg:memisc: "A different interface also based on the PSPP codebase is available in package memisc: see its help for spss.system.file." I have used that package's function successfully (once) on files created by more recent versions of SPSS.