Psychometric properties of the Intentions Toward Infidelity Scale (IIS)

Abstract

This study aimed to adapt the Intentions Toward Infidelity Scale (IIS) to the Brazilian context, knowing its psychometric parameters. Two studies were carried out with people who were in a romantic relationship. Study 1 included 161 participants (mean age = 24.9), who responded to the IIS and demographic questions. Results indicated the one-factor solution for this scale (α = 0.85), whose items showed reasonable discriminative power (theta ranging from -0.5 to 3.0). Study 2 included 236 participants (mean age = 25.5), who answered the same instruments. Results supported the one-factor structure (e.g., CFI = .95 and TLI =.93), which showed invariant across sex (ΔCFI and ΔRMSEA < 0.01). In conclusion, the findings supported the adequacy of the IIS items, but also indicated evidence of its factorial validity and internal consistency, favoring its use in studies looking to investigate the correlates of infidelity.