This study aims to evaluate the effectiveness of standardized patient simulation based on "The De-Escalation Model in Simple Form" on nursing students' perceptions of aggression and perceived learning outcomes. Encountering aggressive and violent patient behavior is a common and challenging experience for nursing students. Simulation-based education offers experiential learning opportunities that can enhance students' confidence and clinical decision-making skills.

The study was designed using a convergent parallel mixed-methods approach. The quantitative component consists of a randomized controlled trial design in which participants will be randomly assigned to either the intervention group or the control group. Primary and secondary outcome measures related to aggression perception and perceived learning will be assessed post-test in both groups.

The intervention group will receive training based on the De-Escalation Model in Simple Form, followed by participation in an aggression management simulation with a standard patient. After the simulation, qualitative data will be collected from participants in the intervention group to examine their experiences, perceptions, and reactions to the intervention and simulation process.

Quantitative and qualitative findings will be analyzed to provide a comprehensive understanding of the intervention's effectiveness and implementation process. The results of this study are expected to contribute to evidence-based educational practices aimed at improving nursing students' skills in managing aggressive patient behavior.

Nursing students frequently encounter aggressive and violent patient behavior during clinical practice, which represents a challenging aspect of professional practice. Inadequate management of aggression can jeopardize the quality of patient care as well as the safety of healthcare workers, patients, and their families. Therefore, developing effective aggression management skills is a critical component of nursing education.

Simulation-based education provides a safe and structured learning environment where nursing students can experience realistic clinical situations without putting patients or themselves at risk. Previous studies have shown that simulation improves students' self-confidence, communication skills, and clinical decision-making abilities. However, evidence regarding structured, model-based simulation interventions specifically designed for aggression management is limited.

This study aims to evaluate the effectiveness of integrated standardized patient simulation with the "De-Escalation Model in Simple Form" on nursing students' perceptions of aggression and perceived learning outcomes.

Research Hypotheses:

H0a: The De-Escalation Model based standardized patient simulation has no statistically significant effect on nursing students' perceptions of aggression.

H1a: The De-Escalation Model based standardized patient simulation has a statistically significant effect on nursing students' perceptions of aggression.

H0b: The De-Escalation Model based standardized patient simulation has no statistically significant effect on nursing students' perceived learning levels.

H1b: The De-Escalation Model based standardized patient simulation has a statistically significant effect on nursing students' perceived learning levels.

The study will conduct a convergent parallel mixed-methods design. Quantitative data will be collected using a pre-test-post-test randomized controlled trial with an intervention group and a control group. Qualitative data will be collected concurrently using a phenomenological approach to explore participants' experiences of the standardized patient simulation. Quantitative and qualitative findings will be analyzed separately and integrated during the interpretation phase.

The study will be conducted in a nursing simulation laboratory within the health sciences faculty of a university.

The study population will consist of fourth-year nursing students enrolled in the Mental Health and Psychiatric Nursing course during the 2025-2026 academic year. A total of 56 students will be included in the study.

Participants will be randomly assigned to either the intervention group or the control group using a simple randomization method, ensuring an equal number of participants in each group. Each group is planned to include 28 participants. Inclusion Criteria are as follows: (i) being 18 years of age or older, (ii) having taken and successfully passed the Mental Health and Psychiatric Nursing course, (iii) agreeing to participate in the study. Exclusion Criteria are as follows: (i) refusing to participate in the study The primary outcome measure of the study, perception of aggression, will be measured using the Perception of Aggression Scale. A high mean score on the functional subscale indicates that aggression is perceived as functional/acceptable, while a high mean score on the dysfunctional subscale indicates that aggression is perceived as dysfunctional/unacceptable. The secondary outcome measure of the study, impact of aggression, will be measured using the Impact of Patient Aggression on Carers Scale. A high score on the scale indicates that individuals are highly affected by aggression. The tertiary outcome measure of the study, perceived learning, will be measured using the Perceived Learning Scale. An increase in the scale score indicates an increase in the level of perceived learning. All three outcome measures will be assessed at baseline and after the intervention in both the intervention and control group. In the final stage, qualitative data will be collected from participants in the intervention group to examine their learning experiences and perceptions regarding the simulation and intervention process.

A standardized patient will be used for the simulation intervention. Prior to participation, the standardized patient will be trained on the simulation scenario, expected behaviors, and procedures to ensure consistency between simulation sessions. Written informed consent will be obtained from the standardized patient before the study begins.

Data collection will be conducted in three consecutive phases: (1) Information and pre-test, (2) simulation intervention, and (3) post-test and qualitative data collection.

In the first phase, eligible participants will be informed about the study procedures, objectives, and their rights as participants, and written informed consent will be obtained. Prior to the intervention, baseline assessments of the outcome measures, including participants' perceptions of aggression and perceived learning levels, will be conducted.

In the second stage, only participants in the intervention group will receive training in "The De-Escalation Model in Simple Form" and then participate in an aggression management simulation with a standardized patient. The simulation will be conducted in small groups using a structured and standardized scenario. During the simulation, nursing students are expected to assess environmental safety, recognize early warning signs of aggression, apply the steps of The De-Escalation Model in Simple Form (setting limits, clarifying the situation, and problem-solving), and use therapeutic communication techniques to manage patient agitation. The simulation focuses on non-physical de-escalation strategies and emphasizes patient and staff safety. Each simulation session will begin with a briefing and conclude with a debriefing session facilitated by the research team.

In the final stage, qualitative data will be collected from participants in the intervention group to examine their learning experiences and perceptions of the simulation and intervention process. Subsequently, final test assessments will be administered to both the intervention and control group using the same outcome measures.

IBM SPSS Statistics 27 software will be used for the statistical calculations and analyses of the quantitative data in the study. When evaluating the study data, frequencies (number, percentage) will be used for categorical variables, and descriptive statistics (mean, standard deviation, median, minimum, maximum) will be used for numerical variables. The normality assumptions of numerical variables will be examined using the Kolmogorov Smirnov normality test. Depending on the normality distribution, parametric (Independent Samples T Test, etc.) or non-parametric (Mann Whitney U, etc.) statistical methods will be used. Statistical significance in the analyses will be interpreted at the p<0.05 level. In the qualitative part of this mixed-methods research, the written responses given by students to the questions asked during the debriefing phase will be examined using the content analysis method from qualitative data analysis methods. In this analysis, the written responses given to the questions asked to students during the simulation's analysis phase will be coded. The data will be organized by analyzing it and placing it into relevant categories. The reporting phase, which is the final step of the content analysis method, will be completed by presenting the content analysis steps and findings.

Participation in this study will be voluntary. All participants will be informed about the study's objectives, procedures, and their rights as participants, and written informed consent will be obtained prior to data collection. Simulation sessions may be video recorded, with the participants' consent, solely for educational and evaluation purposes. All recordings will be stored securely, accessible only to the research team, and permanently deleted after the study is completed. Confidentiality will be ensured through the use of coded data collection forms and secure, password-protected digital storage systems. No personally identifiable information will be included in the data sets, and study data will be used solely for research purposes and will not be shared with third parties. Upon completion of the study, participants in the control group will also be offered the same training and simulation intervention.

Inclusion Criteria:

• being 18 years of age
• having taken and successfully passed the Mental Health and Psychiatric Nursing course
• agreeing to participate in the study

Exclusion Criteria:

• refusing to participate in the study