I see that the GQ variable is available for ASEC samples but not basic monthlies. Is there another variable or method for identifying the handful of GQ respondents in the basic monthly samples? This would correspond to the variable in the CPS-published tables called HRHTYPE, which has values of 9 or 10 for GQ respondents.
IPUMS has not yet harmonized the HRHTYPE variable; however, we continue to add more basic monthly variables. The greater the perceived demand by IPUMS users, the sooner a variable is likely to be released.
To identify group quarters in non-ASEC samples, you must link IPUMS-CPS data to the source data files available through NBER. The IPUMS household linking variables can be found here. To link person records, you will also need to use LINENO, AGE, and SEX. The corresponding NBER variables are identified in this documentation.
Hope this helps.