The Defending Responses Against Sexual Harassment (DEFEND-SH) Instrument in Adolescents: Psychometric Properties and Measurement Invariance.

INTRODUCTION: Most instruments designed to assess bystander defending responses against sexual harassment have been validated primarily in university contexts and with the North American population, which limits their generalizability to adolescent populations in other cultures. To address this gap, this study aimed to explore the psychometric properties of a new measure named Defending Responses Against Sexual Harassment Instrument (DEFEND-SH) in a Spanish sample. METHODS: A cross-sectional study was conducted during the 2023-2024 academic year. The sample comprised 1250 Spanish students from six educational centers, aged 12 to 19 years (M = 14.86; 51.3% boys). The statistical analyses included confirmatory factor analysis, multigroup analyses by gender and response type (hypothetical vs. actual). RESULTS: The results supported a four-factor structure encompassing different defending responses in the high school context: supporting the victim, seeking help from an adult, mobilizing other bystanders, and confronting the aggressor. DEFEND-SH demonstrated full measurement invariance across gender and response type (hypothetical vs. actual). Adolescents reporting hypothetical responses scored higher than those reporting actual behaviors, and girls scored higher than boys across all dimensions. Regarding criterion-related validity, tolerance toward sexual harassment was negatively correlated with all four defending responses, particularly supporting the victim. In contrast, self-efficacy and moral responsibility emotions showed significant positive associations with the defending responses. CONCLUSIONS: The DEFEND-SH instrument is shown to be a useful tool for analyzing the defending responses of adolescents against sexual harassment.