Tethering theory to timescale: Advances in measuring interpersonal complementarity and covariation

•Interpersonal processes occur at the between- and within- situation levels.•In EMA data, complementarity is often only measured between-situations.•Within-situation agentic complementarity more strongly relates to psychopathology.•Within-situation interpersonal covariation more strongly relates to psychopathology.•Clinical interventions also distinguished by between (who) and within (when) levels.