Missing wtfinl in monthly CPS before 2019

I downloaded monthly data from 2009-2022, but wtfinl is missing for all but the most recent 4 years. I should note that last week a student turned in an assignment using 2016-2022 and reported wtfinl only started in 2019, which I assumed was user error on his part. Thus, I just pulled the simple extract referenced above and had the same problem. Any ideas?

I was not able to replicate the issue you are describing; I submitted an extract with all basic monthly samples for 2009-2022 and am getting WTFINL values in all years. I suspect the problem is related to sample selection rather than the underlying data. By default, IPUMS CPS includes the 2009-forward ASEC and the most recent basic monthly samples (~2 years of data or 24 months). Without separating out ASEC samples from basic monthly samples and only using the YEAR variable, it will appear as though WTFINL is missing prior to 2019 because WTFINL is only available for basic monthly samples and not ASEC samples (these should be weighted using ASECWT). If you, and the student, resubmit your requests with basic monthly instead of ASEC files for these earlier years, you should get values for WTFINL.