Three groups, two regimes. Homophily means each group prefers its own. Status hierarchy means everyone prefers the top group, which is selective and rejects below. The two regimes can produce nearly identical observed pairings — yet the underlying preferences are entirely different.
Endogamy is sometimes read as evidence of in-group preference — people choosing their own. But the same observed pattern can be produced by exclusion: a high-status group closes itself off, and lower-status groups end up matched within their own not because they preferred to but because they were rejected from above. Realised unions are symmetric — a couple is a couple, regardless of who chose whom — while preferences are directed. From observed marriages and cohabitations alone, we cannot tell whether endogamy reflects warmth toward one's own group or coldness toward others. Distinguishing them requires data the partner market rarely provides: stated preferences, dating-app responses, vignette experiments. This is a baseline identification problem in assortative-mating research, not a special case.