For 1977-2015 I see that 9.3% of individuals age 20-65 have a spouse (sploc>0) but report that they are not married (marst>2) and 1.77% don’t have a spouse (sploc=0) but report that they are married (marst<=2). Why is there a disconnect between sploc and marst about the marital status. Particularly the 9.3% is quite a big disconnect. And which variable should be used in the analysis?
Regarding cases with SPLOC >0 and MARST >2, these appear to be cohabiting unmarried couples which IPUMS identifies as spouses in SPLOC. All of the cases that I found coded the spouse with RELATE = 1114 (unmarried spouse). RELATE is created using information from the original census variable RELHD (see UH_RELHD_B4), which reports the respondent’s relationship to the household head. In this instance, the spouse is labeled as being either the head’s unmarried partner with relatives or the head’s unmarried partner without relatives, which causes SPLOC to tag them as the household head’s spouse.
Cases with SPLOC = 0 and MARST <= 2 are explained by the fact that the vast majority of these respondents are coded with MARST = 2 (married, spouse absent). The census bureau page on subject definitions notes that this group includes married people living apart because either the husband or wife was employed and living at a considerable distance from home, was serving away from home in the Armed Forces, had moved to another area, or had a different place of residence for any other reason except separation as defined above. This results in the spouse not appearing in the household roster even though the household head is married. I suspect any other cases where SPLOC = 0 and the respondent reports being married are due to the absence of a logical relationship pairing. A person might report being married, but their RELATE and AGE value don’t yield a likely coresident spouse as per our algorithm.
I hope this is helpful in figuring out whether to use SPLOC or MARST in your analysis.