Table 1 Specification of the multi-level actor-partner interdependence model
Levels | Predictor labels | Predictors |
|---|---|---|
Individual actor and individual partner (i) | X_actor, X_partner | Age, race/ethnicity, education, sexual orientation, serostatus, unprotected anal intercourse with a man other than main partner in past 3 months, agreements about sex outside the relationship |
Dyad (j) | Z | Duration of relationship with main partner (average); unprotected anal intercourse in last year with main partner; dyadic differences in age, education, race/ethnicity, sexual orientation, and agreements about sex outside the relationship |
1. Individual level model:  g‒ 1(mij) = η ij  = β 0j  + β 1j (X _ actor) ij  + β 2j (X _ partner) ij | ||
  Individual level residual term is omitted because its variance is assumed fixed | ||
  η ij is the log odds of the outcome | ||
  β 0j is the within-dyad intercept in dyad j | ||
  β 1j is the slope of ηij on xij in dyad j | ||
2. Dyad level model:  β 0j  = γ 00  + γ 01 (Z) j  + u oj, β 1j  = γ 10 ,  β 2j  = γ 20 | ||
  Dyad level slopes are fixed | ||
  u 0j , the random intercept, is the only random effect | ||
  γ 00 is the average intercept across dyads | ||
3. Final model:  η ij  = γ 00  + γ 01 (Z) j  + γ 10 (X _ actor) ij  + γ 20 (X _ partner) ij  + u oj, | ||
  This model contains one random intercept (no random slopes, no interaction terms) | ||