Documentation on the layout of a DDI file

Hello, I was wondering if there is any documentation on the layout of the DDI file, meaning a description of the sections and the types of information included. I have downloaded some DDI files and I can parse the XML, but I am not sure about variations in DDI layouts, etc. So I was hoping to look at the DDI specification, to make sure I anticipate the variations. That way, my code is a bit less fragile.


If you can share more about how your code is leveraging the DDI files, that would help me direct you towards the most relevant information. I can check with a colleague about which specification IPUMS is currently using, but am sharing the DDI Lifecycle 3.3 and DDI Codebook 2.5 for your reference.

Assuming you are simply hoping to parse the information to read a fixed-width data file into a statistical analysis software package, I would recommend using the corresponding syntax files instead (i.e., fixed width data extracts will include set-up files to load your data into Stata, SAS, and SPSS). You may also be interested in using ipumsr or ipusmpy, which allow you to work with IPUMS extracts more easily in Python and R respectively, including by parsing the DDI.

I will note that neither of these methods captures the full range of information contained in the DDI codebooks, but these are sufficient for the most common use case (i.e., opening and analyzing an IPUMS data file). Please let me know if you have a different use case for the information in the DDI codebook.

Thanks @KariWilliams , yep I was able to find what I needed in that DDI Codebook. Thanks for your help.

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