Peer-Group Assertive Communication and Verbal Bullying Scores Among High-School Students: A Quasi-Experimental Study

Noval Maulana (Qamarul Huda Badaruddin University, Bagu, West Lombok, West Nusa Tenggara)
Maulin Halimatunnisa (Qamarul Huda Badaruddin University, Bagu, West Lombok, West Nusa Tenggara)
Suswinda Yuli Sutomo (Qamarul Huda Badaruddin University, Bagu, West Lombok, West Nusa Tenggara)
D Mustamu Qamal Pa’ni (Qamarul Huda Badaruddin University, Bagu, West Lombok, West Nusa Tenggara)

Gaster
Vol 24 No 2 (2026): AGUSTUS

Introduction: Peer-assisted assertive communication education may support adolescents’ interpersonal skills, but changes in bullying questionnaire responses do not necessarily indicate fewer bullying incidents. Objective: To describe pretest–posttest verbal-bullying questionnaire scores and unadjusted posttest differences following ASERTIF-S education in high-school students. Method: This two-group quasi-experimental study included 79 Grade 11 students (intervention, n = 40; comparison, n = 39). A 22-item questionnaire was administered before and after the educational activity. Wilcoxon signed-rank and Mann–Whitney U tests were reported. Result: The intervention group had 37 negative signed ranks (Z = 5.305; p < 0.001) and the comparison group had 10 (Z = 2.970; p = 0.003). Posttest ranks differed (U = 107; p < 0.001). Baseline very-frequent response categories differed considerably (35.0% vs 79.5%). Conclusion: Questionnaire scores differed within and between groups, but substantial baseline imbalance and absent baseline-adjusted analysis prevent a causal conclusion that the activity reduced or prevented bullying.