SPSS Data File Specifications
Q can analyze any SPSS data file (.sav). However, analysis will be substantially easier and faster if these specifications are used when creating the file.
Languages and Character Encodings
If you load data in Q and see ? characters where there should be text then you have probably loaded an SPSS file from another language that was saved using Code Page mode.
Text in SPSS files can be encoded in two modes:
- In Unicode mode (the default from SPSS version 20 onwards), characters from all languages will load correctly in Q.
- In Code Page mode (the older default), only characters from your computer's default code page can be used. Other characters will appear as ? characters. In Code Page mode your data file can only include characters that are normal in your language, or English. For example, a Japanese SPSS file in Code Page mode can only be used in Q on a Japanese computer.
If you have data that cannot fit into a single encoding then the SPSS file must be made using Unicode mode. e.g. Japanese and Chinese, or English (latin) and Russian (cyrillic).
Fixing an SPSS File from Another Language
You will need to do one of the following:
- Ask your data provider to give you an SPSS file in Unicode mode.
- Run Q on a computer that has been set up to use the same language as is in the data file. If you do this then the project you create on that computer will work on any other computer running Q, regardless of that computer's language (because Q remembers the language of the data file in the Q project file).
- Run SPSS on a computer that has been set up to use the same language as is in the data file. Then switch the file to Unicode mode and resave the SPSS file.
Be aware that if text is wrong in SPSS then it will also be wrong in Q. This can occur when the data has been badly converted between different languages.
Compatible Languages in Code Page Mode
- English is compatible with all code pages, and so can be present in a Code Page mode SPSS file from any country.
- Western European languages share the same "code page" and so can coexist in Code Page mode.
- While sharing many characters, Japanese and Chinese code pages are not compatible.
- There are multiple code pages for Chinese. For example, data from Hong Kong will generally not work with computers in mainland China, and vice-versa.
The following specifications are for more advanced data types:
- File Formats Supported by Q
- Data File Setup for Tracking Studies
- Data File Setup for Studies with Multiple Versions of the Questionnaire
- Data File Setup for Questions with Rotations or Randomization
- MaxDiff Specifications contains instructions for the specifications for MaxDiff experiments.
- Experiments Specifications contains specifications for the set up of conjoint, discrete choice and other types of choice experiments.
Further reading: SPSS Alternatives