Comparative research involving consensually non-monogamous (CNM) relationships and outcomes related to well-being continues to grow as an area of interest within sexual science. However, claims of sameness and/or difference between groups rely on two critical, yet widely under-appreciated assumptions: that the concepts being compared between groups are the same (i.e., measurement invariance), and that logically and statistically coherent procedures are used for evaluating sameness (i.e., equivalence testing). We evaluated the state of measurement invariance and equivalence across three studies, involving different types of CNM comparisons (i.e., relationship types, partner types) and designs (analysis of primary individual data, primary dyadic data, and secondary data). Our invariance tests of CNM compared to monogamous individuals (Study 1) and “primary” compared to “secondary” partners in dyadic appraisal of CNM individuals (Study 2) revealed that many measures of well-being failed to replicate their measurement models and were not generalizable across relationship types or partner types. Our reanalyses of existing comparative CNM effects using individual and meta-analyzed equivalence tests (Study 3), meanwhile, indicated that this literature requires more consistent reporting practices and larger samples, as most studies produced uninformative tests of equivalence. Our results illustrate the importance of auxiliary hypothesis evaluation and statistical procedure selection for generating informative comparative tests. Our findings also highlight potential divergences in social construction of well-being. We offer suggestions for researchers, reviewers, and editors in terms of needed methodological reforms for future comparative CNM research.

Sexual health reflects physical, emotional, mental, and social elements of sexual well-being. Researchers often position self-esteem (i.e., global or domain-specific evaluations of self) as a key correlate of sexual health. We present the first comprehensive meta-analysis of correlations between self-esteem and sexual health. Our synthesis includes 305 samples from 255 articles, containing 870 correlations from 191,161 unique participants. The overall correlation between self-esteem and sexual health was positive and small (r = .12, 95% CI: .09, .15), characterised by considerable heterogeneity and robust to different corrections. Sexual functioning (r = .27, 95% CI: .21, .34) was more strongly associated with self-esteem than were safe sex (r = .10, 95% CI: .07, .13) and sexual consent (r = .19, 95% CI: .13, .24), and sexual permissiveness was unassociated with self-esteem (r = −.02, 95% CI: -.05, .008). Most moderators were nonsignificant, although moderator data were inconsistently available, and samples were North American-centric. Evidence of publication bias was inconsistent, and study quality, theory usage, and background research were not reliably associated with study outcomes. Our synthesis suggests a need for more specific theories of self-esteem corresponding to unique domains of sexual, highlighting a need for future theorising and research.

Past research consistently suggests that singles are stigmatized, but do they constitute a stigmatized group? The current research provides deeper insight into the stigmatization of single people by understanding their ‘group-y’ nature, and how group identification and perception map onto discrimination and prejudice. Study 1 examined the extent to which singles identify as part of a group. Participants were assigned a novel minimal group identity and then completed measures of group identification for four group memberships (e.g., minimal group, relationship status, sexual orientation, nationality). As hypothesized, singles' identification with other singles was lower compared to their identification with other identities—as well as compared to partnered people’s group identification. Contrary to our hypothesis, singles did not perceive less discrimination towards singles relative to other aspects of their identity. Study 2 examined the extent to which singles are perceived as a group and the extent to which their group-y-ness vs. perceived responsibility for their group membership explains the acceptability of prejudice towards them. Participants completed measures of entitativity and perceived responsibility for similar out-group identities as in Study 1 (e.g., single people vs. people in romantic relationships). As hypothesized, singles were rated lower in entitativity than people in romantic relationships and other groups. Prejudice towards singles was also more acceptable than prejudice towards national and sexual orientation groups. Accordingly, perceived responsibility was a stronger predictor of the acceptability of prejudice towards singles than their entitativity. We discuss the importance of group-based theoretical perspectives for understanding the current and future stigmatization and well-being of singles.