I’m merging IPUMS-CPS basic monthly files (2000-2016) with NBER’s to add variables that the first lack. Unfortunately, even though, I’ve been able to sucessfully merge most of them using the instructions outined here Should the IPUMS-CPS and NBER CPS data match?, i.e. have found no age or sex difference, I haven’t achieved the same with the September 2000, April 2001, June 2001 and February 2002 surveys.
For Sep 2000 and Feb 2002, I’m able to find matches (based on hrhhid, huhhnum, hrsample, hrsersuf, statefip and lineno) for all observations in the IPUMS-CPS files, which equal the number of obs. in the NBER’s dimissing non-respondents (lineno==-1). Nevertheless, I don’t understand why in both surveys many matched observations differ on age: 6,429 out of 121,658 and 3,150 out of 140,775, respectively.
Finally, for Apr 2001 and Jun 2001, besides getting 22,773 and 22,770 unmatched observations in the IPUMS-CPS files (my master data), I also find matched observations that differ on age or sex. In the first survey, I find 617 matched observations with different age and 18 with different sex; while in the second one, 715 and 30, respectively.
Why do I find these age/sex differences for matched observations in all four surveys? And why do I get so many unmatched observations in the IPUMS-CPS files for Apr and Jun 2001?
I’ve realized that in all four surveys almost all of the troubling observations have hrsersuf==“0” (6,406 for Sep 2000 and 3,140 for Feb 2002; 22,701 for Apr 2001 and 22,699 for Jun 2001), but I don’t know if/how this fact could account for the merge results I get.
Just in case, before merging the surveys prior to May 2004, I used the command: replace hrsersuf="-1" if hrsersuf==“0” in the IPUMS-CPS files to make this variable coding consistent with NBER’s.
I would really appreciate it if you could please help solve the merging issues I’m facing with the four basic monthly surveys.
Thank you so much in advance,