IPUMS ACS five-year sample occ variable

Hi I use ACS five-year estimates and found that the occ variable in 2005-2009 five year sample are not all four digits - some are 2, some are 3 and some are 4. see the snapshot. I wonder if there’s a consistent four digit occ classification that I can use (or a crosswalk). I am also a bit confused by the occ classification code, i.e. which year uses which classification, as there seems to be inconsistency in the content of the two links:IPUMS USA | ACS Occupation Codes (OCC) 2000-2017 and IPUMS USA | ACS Occupation Crosswalk 2000 Onward -- OCC and OCCSOC. One says 2012 uses the same classification as 2016, another says not. I wonder if there is more clarity on this issue. Many thanks!

Regarding your first question, the codes are stored as a numeric variable, so codes in the range 0001-0009 will have only 1 digit, 0010-0099 will have only two digits, and codes 0100-0999 will have only 3 digits, while codes 1000-9999 will have the full 4 digits.

For your second question, the ACS uses the same occupation codes for 2012-2017. 2010 and 2011 use a different set of codes. Sorry about the confusing documentation, I will let the IPUMS USA team know that this needs to be fixed.

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Thanks a lot Matt! I have a follow up question: per the acs documentation, it says that the occ variable in the multiyear sample uses the classification of the year in which the sample was drawn. However, in the attached, the occ variable in multyear==2015 seems to use 2018 acs classification, as per this link, the occ code 2545 only appears in acs 2018 classification, and not the acs 2012-17 classificaiton. IPUMS USA | ACS Occupation Crosswalk 2000 Onward -- OCC and OCCSOC.

I wonder if in the five year sample, the occ classification has been readjusted to use the classification of the final year. Many thanks!

The note in the documentation is not universally true. For some 5-year samples (such as 2011-2015), the original OCC codes are used. For others, such as 2015-2019, OCC is recoded to the system used in the final year. Sorry for the confusion. The IPUMS USA team is aware of this documentation problem and are working to clarify which samples use the original codes.

Many thanks Matt, looking forward to the clarification!