There are two variables that indicate the interview month relationship to householder: ERELRPE and ERELRP. Users should use the first one, which is a detailed 18-category variable rather than the collapsed version, ERELRP. The latter is a recode that is consistent with the relationship question categories in earlier SIPP panels, but only includes 13 categories, which do not identify same-sex married spouses, same-sex unmarried partners, nieces/nephews nor several in-law categories (parent, child or sibling). In addition, the ERELRP and ERELRPE differ for some cases, for which ERELRPE should be used.