Background: Clinical communication is a core competency in nursing practice and is pivotal to the quality, safety, and person-centred delivery of care. Effective communication supports treatment adherence, reduces errors, enhances patient and family satisfaction, and contributes to nurses' professional wellbeing. Despite the acknowledged importance of these skills, nursing students frequently report difficulties communicating with confidence and assertiveness in clinical settings. Although simulation is widely regarded as an innovative educational approach, evidence regarding its specific impact on the development of clinical communication skills-and on students' self-perceived communication competence-during the early stages of nursing education remains limited.

Methods: This protocol describes a parallel-group randomised controlled trial with 1:1 allocation, to be conducted at a private higher education institution in Portugal. First-year undergraduate nursing students enrolling for the first time in the Helping Relationship course unit will be eligible. The intervention group will participate in clinical simulation sessions, whereas the control group will receive conventional teaching comprising role-play, group discussion, and case analysis. Both groups will complete 10 contact hours delivered across three sessions over the semester. The primary outcomes will be: (a) clinical communication competence, assessed using the Interpersonal Communication Assessment Scale (ICAS), and (b) perceived self-efficacy, measured with the Self-Efficacy Questionnaire (SE-12), both administered pre- and post-intervention. Satisfaction with the educational experience will be assessed as a secondary outcome. Analyses will follow the intention-to-treat principle, complemented by a per-protocol analysis.

Discussion: This study will help to clarify whether clinical simulation is superior to conventional teaching in fostering communication skills and students' self-perceived communication competence during the early stages of undergraduate nursing education. The findings may support the early integration of simulation within nursing curricula and inform the design of educational interventions that promote the development of professionals who are more competent and confident in clinical communication, with a direct impact on the quality and safety of care delivery.

Methods/Design This protocol was developed in accordance with the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) guidelines.

Patient and Public Involvement, Trial Design No target-population involvement was undertaken during the planning of this study, as input from first-year undergraduate students-who have neither clinical practice nor prior exposure to the pedagogical strategies under evaluation-could have been driven by assumptions or perceptions with limited grounding. Conversely, the literature indicates that when the target population is inexperienced with the educational strategy being assessed, it is more appropriate to involve stakeholders with greater expertise at the design stage, such as academic staff, given their knowledge and experience, this approach was adopted in the present study.

Participants, Interventions, and Outcomes Trial setting The study will be conducted at a private higher education institution for health sciences in Portugal. It is a parallel-group randomised controlled trial with a superiority framework, aiming to evaluate whether simulation as an educational strategy leads to greater improvements in clinical communication skills than conventional teaching. In this trial, the superiority assumption is grounded in the objective of demonstrating that the intervention is superior-that is, that it yields a statistically significantly better outcome on the primary endpoint.

The unit of randomisation will be the individual student; that is, each student will be randomly allocated to one of the study groups. Allocation will be performed at a 1:1 ratio, with half of the students assigned to the intervention group (simulation) and the other half to the control group (conventional teaching-role-play).

Eligibility criteria Participants will be required to meet the following inclusion criteria: (a) active enrolment in the first year of the undergraduate Nursing degree programme, and (b) first-time attendance of the Helping Relationship course unit. Under these assumptions, no additional exclusion criteria will be applied.

Facilitators delivering the intervention will be academic staff from ESSNorteCVP who meet the following criteria: (a) certified training in clinical simulation, (b) a minimum of two years' experience in nursing education, and (c) attendance at the course preparation meeting to ensure familiarity with the study procedures.

Intervention and comparator Participants in the intervention and control groups will receive different pedagogical approaches, both delivered within the 10 contact hours of laboratory practice sessions in the Helping Relationship course unit. The main characteristics of the intervention and the comparator are presented below.

Intervention (Clinical Simulation) The intervention consists of clinical simulation sessions using standardised patients who portray clients and/or their relatives in scenarios grounded in nursing clinical practice. Each simulation session follows a structured pedagogical sequence comprising three core components: (i) a briefing, delivered by an academic staff member to contextualise the scenario and clarify learning objectives; (ii) hands-on simulation, during which students actively engage with the standardised patient; and (iii) a structured debriefing, facilitated by academic staff together with the students and guided by the TALK debriefing tool.

All sessions are delivered by academic staff trained in simulation-based education. The number of participants is limited to a maximum of 13 students per session, ensuring optimal interaction and feedback. Simulation activities take place at Simlab@Learn, within designated simulation facilities specifically equipped for this type of educational strategy.

The total intervention comprises 10 contact hours, delivered during the second semester in accordance with the course timetable. These hours are organised into two 4-hour blocks and one 2-hour block.

Simulation scenarios may be adapted in terms of complexity according to students' observed performance, while preserving consistency with the predefined educational objectives.

Educational materials used in the intervention include clinical scenarios enacted by standardised patients, observation and performance checklists, and structured debriefing support sheets. These materials are mandatory for the implementation of the intervention and are made available to facilitators via the institutional platform (INFORDocente). Participants in the intervention group do not have access to the educational strategies used in the control group.

Comparator (Conventional Teaching) The comparator consists of conventional laboratory practice sessions, incorporating informal student-to-student role-play, group discussion, and analysis of clinical cases, all conducted under the supervision of academic staff. These sessions do not involve the use of standardised patients or structured simulation methodologies.

Sessions are delivered by academic staff without specific training in simulation-based education. As in the intervention group, participation is limited to a maximum of 13 students per session. Teaching activities take place at Simlab@Learn, specifically within the relational laboratory.

The comparator also comprises 10 contact hours, delivered during the second semester and organised into two 4-hour blocks and one 2-hour block, in alignment with the course timetable.

Educational materials consist of vignettes that provide brief descriptions of clinical situations or cases to support discussion and analysis. Participants in the comparator group do not have access to the simulation-based strategies used in the intervention group.

Although this study does not involve invasive interventions or direct clinical risk, criteria have been defined for discontinuing a student's participation in either the intervention or the control group in order to safeguard participants' wellbeing and the validity of the data. A student may interrupt or discontinue participation in the following circumstances: (a) upon request, by withdrawing informed consent; (b) exacerbated emotional distress (e.g., heightened anxiety), whether self-reported or perceived by the academic staff member; (c) withdrawal from the course unit; or (d) completion of the course unit via the examination-based assessment option.

To maximise student adherence to the study, the following measures will be implemented: (a) clear engagement of students within the informed consent process; (b) provision, in the first session of the course unit by the course lead, of information regarding the aims, duration, and benefits of participation; and (c) delivery of reminders via INFOREstudante prior to each laboratory practice session.

Participant adherence will be monitored through attendance registers for all sessions, duly signed by the students and the academic staff member.

To ensure fidelity to the pedagogical approach, the following measures will be undertaken: (a) the study and its pedagogical alignment will be presented at the course preparation meeting; (b) all required materials will be made available to academic staff at that meeting; (c) at least 50% of the total laboratory practice (PL) teaching hours (i.e., a minimum of 5 hours) will be observed by a member of the research team to verify (1) the conduct of the briefing and debriefing, (2) the use of the scenarios, (3) the absence of simulation elements within conventional teaching, and (4) adherence to the planned duration of each session; and (d) regular meetings will be held with academic staff between laboratory practice sessions to review implementation processes and procedures.

For data analysis purposes, participants will be classified as follows: (a) protocol-adherent-attendance at ≥80% of the allocated laboratory practice sessions and completion of the planned educational activities; (b) protocol-non-adherent-attendance below 80% and/or non-completion of the planned educational activities; and (c) students who discontinue participation before completing the first laboratory practice session or who withdraw voluntarily-who will be excluded from the final analysis. The ≥80% threshold is justified on two grounds: (a) pedagogical logistics, as the laboratory practice sessions comprise two 4-hour blocks and one 2-hour block; thus, attendance at the two 4-hour sessions is expected to represent adequate exposure to the intervention to support a per-protocol analysis; and (b) the literature in this field indicates that adherence levels above 75% are recommended for studies evaluating educational approaches.

During the study period, students may continue to attend all other course units scheduled within the first-year undergraduate nursing curriculum, provided these do not include specific interventions focused on clinical communication in a simulated context. Students will be informed of this restriction at the time of consent and will be asked to notify the research team if they are enrolled in any such activities. Nonetheless, participants will be invited to complete a brief questionnaire at the end of the intervention regarding: (a) whether they took part in any other activities related to clinical communication or simulation; (b) the type, duration, and setting of those activities; and (c) whether they believe these activities influenced their performance in the laboratory practice sessions. This information may be relevant to a more nuanced interpretation of the study findings.

Outcomes The primary outcomes focus on students' level of clinical communication competence, assessed using the Interpersonal Communication Assessment Scale (ICAS), which has been adapted and validated for the Portuguese population, specifically among nursing students [46]. As well as perceived self-efficacy in clinical communication skills, assessed using the Self-Efficacy Questionnaire (SE-12). This instrument has been used in both national and international studies conducted in educational settings, which supports the decision to employ it in the present trial.

Secondary outcomes relate to satisfaction with the learning experience. Clinical communication competence is assessed using the Interpersonal Communication Assessment Scale (ICAS). This outcome is measured at two time points: pre-intervention and post-intervention. The primary analytic approach consists of calculating change scores between baseline and post-intervention assessments. Results will be reported as means and standard deviations, stratified by study group.

Perceived self-efficacy in clinical communication skills is evaluated using the Self-Efficacy Questionnaire (SE-12). As with clinical communication competence, this outcome is assessed at pre-intervention and post-intervention. Analysis will focus on change scores derived from differences between the two assessment points. Outcomes will be summarised using means and standard deviations by group.

Student satisfaction with the educational strategy is measured using a questionnaire administered post-intervention only. For this outcome, the final score will be analysed. Results will be presented as means and standard deviations by group.

Harms In this study, an "adverse event" is defined as any negative occurrence related to participation in either the intervention or the control condition, such as: (a) significant anxiety during or after sessions; (b) frustration, humiliation, and/or inability to engage with the simulated scenario; and (c) any perceived negative consequence leading to changes in emotional wellbeing or withdrawal from participation. During sessions, the lecturer/facilitator will use an observation checklist to monitor signs of emotional distress, including avoidance behaviour, crying, restlessness, sweating, facial flushing, and-where indicated-participants may be referred to the institution's Mental Health and Wellbeing Service. Records of adverse events will be maintained throughout the 10 hours of laboratory practice teaching and filed together with the other study documentation. Withdrawal due to severe emotional distress will be classified as a serious adverse event related to the intervention.

Participant timeline The study will be conducted during the period in which the laboratory practice (PL) sessions of the course unit are delivered, in the second semester of the academic year. Participation will comprise a theory-practice session for recruitment and informed consent (the first session of the course unit), a pre-intervention assessment (at the start of the first PL session), three practical sessions (10 contact hours), and a post-intervention assessment (at the end of the final PL session).

An additional follow-up assessment will be undertaken 8 weeks after the intervention (i.e., after the final PL session of the course unit) to examine the maintenance of gains and potential transfer of communication skills acquired through simulation versus role-play. Comparative research in education also recommends repeated assessments to identify differences in the durability of effects across pedagogical methods. All study-related activities will take place within scheduled teaching hours.

Sample size Sample size will be calculated based on the findings of the pilot study using G*Power software. The intervention effect (between-group mean difference and pooled standard deviation) obtained from the pilot study will be converted into an effect size (Cohen's d). An independent-samples t test will be assumed, with a 5% significance level (α = 0.05) and 80% statistical power (1-β = 0.80). The final sample size will be further inflated to account for anticipated attrition or withdrawals, estimated at approximately 10-20%, to ensure the robustness of the results.

Recruitment Participants will be recruited from first-year undergraduate nursing students enrolled in the Helping Relationship course unit. Study information will be delivered face-to-face in the classroom by the principal investigator, with support from the course teaching team. The study will be introduced, questions will be addressed, and the informed consent form will be provided. Students will be informed that participation is entirely voluntary and will have no consequences for academic assessment. Recruitment will take place at the beginning of the second semester, prior to the start of the laboratory practice sessions, to ensure that all participants can be randomised before the intervention begins.

If the required sample size is not achieved within a single academic year, the study will be replicated in subsequent years using the same experimental design, inclusion/exclusion criteria, procedures, and data collection instruments in order to ensure adequate statistical power.

Assignment of interventions Randomization: Sequence generation The random allocation sequence will be generated by a member of the research team who is not directly involved in data collection or intervention delivery, in order to ensure procedural impartiality. Microsoft Excel will be used to generate the sequence with a 1:1 allocation ratio (intervention vs control). The generated sequence will be kept confidential until allocation, thereby ensuring allocation concealment.

Following the usual student enrolment procedures for the course unit, simple randomisation will be adopted for the purposes of this study, with students randomly assigned across four laboratory practice groups (PL1, PL2, PL3, PL4). In each academic year, first-year students will be randomly allocated in a 1:1 ratio to one of two study arms: (a) the experimental group (n = 2 groups), which will receive the simulation intervention, and (b) the control group (n = 2 groups), which will continue with conventional teaching. Randomisation will be undertaken by a researcher external to the intervention implementation process using a computerised random number generator. To ensure allocation concealment until implementation, the randomisation sequence will be kept confidential and stored in a password-protected digital format. This process will be repeated in each academic year until the sample size defined by the pilot study is achieved.

No stratification factors will be used, as participants are drawn from the same curricular year and share similar academic characteristics.

Allocation concealment mechanism Researchers responsible for participant enrolment and intervention delivery will not have prior access to the allocation sequence, thereby ensuring allocation concealment until students are assigned to either the control or experimental group. Following generation of the sequence, group allocation will be disclosed only immediately before the intervention commences.

Implementation Participating students will be recruited and enrolled in the study by another member of the research team who is responsible for this task. This individual will not have access to the randomisation sequence. To ensure confidentiality and process integrity, the allocation list will be stored digitally and will be accessible only to the person responsible for generating it.

Blinding Given the educational nature of the intervention, it will not be feasible to blind participants or the facilitators/lecturers delivering the sessions, as both will necessarily be aware of the activity being undertaken. Nevertheless, because the participants are first-year students with no prior exposure to the institution, the study briefing will not describe in detail the specific pedagogical strategy to which each student will be assigned, with the aim of enhancing participant blinding to the extent possible and thereby reducing social desirability and other expectancy-related biases.

Clinical communication outcomes will be self-assessed by participants using the Interpersonal Communication Assessment Scale (ICAS) and the Self-Efficacy Questionnaire (SE-12), as these are self-report instruments and the outcomes of interest are grounded in participants' own perceptions. Questionnaires will be distributed by an independent assessor and placed by participants into a sealed box, which will subsequently be collected by the same assessor. The data will then be analysed by a member of the research team who was not involved in intervention delivery or data collection, thereby ensuring partial blinding at the statistical analysis stage. Each questionnaire will be assigned a unique code (I1, I2, I3, etc., for the intervention group, and C1, C2, C3, and so forth, for the control group).

Data collection, management, and analysis Data collection methods Data will be collected in paper format. In the pilot study, the questionnaires will undergo pre-testing to assess clarity, usability, and response consistency, thereby ensuring their suitability for the present study. External assessors will receive standardised training on the use of the instruments prior to the start of data collection to ensure procedural safety and consistency during the data collection sessions.

A sociodemographic questionnaire will be administered to characterise the sample. The following data will be collected: (a) age, (b) sex, (c) prior professional experience in the health sector, and (d) higher education entry grade. These variables are commonly included in experimental nursing education studies, as they may influence learning, communication performance, and self-efficacy.

The same questionnaire will also include the Interpersonal Communication Assessment Scale (ICAS). The Portuguese version has demonstrated high internal consistency, with a Cronbach's alpha of 0.939 for the total scale and values ranging from 0.795 to 0.890 across subscales, indicating good reliability. It has also shown excellent test-retest stability and is therefore an appropriate tool for assessing communication competence, supporting its use in the present study.

In addition, it will include the Self-Efficacy Questionnaire (SE-12), a 12-item instrument that demonstrates excellent internal consistency (α = 0.95) and construct validity, and is sensitive to differences in experience level. A study to translate, culturally adapt, and evaluate the psychometric properties of this instrument in nursing students is currently underway. If that study has not been completed by the start of the present investigation, its psychometric properties-specifically internal consistency (Cronbach's alpha) and validity-will be examined within this study sample. This approach will ensure the instrument's suitability for the Portuguese context prior to its final use in the outcome analyses.

Finally, with regard to the questionnaire assessing satisfaction with the educational experience, students will be asked to respond to six items: (a) alignment between learning objectives and teaching-learning methods; (b) interest in the content delivered; (c) adequacy of the number of students in laboratory practice sessions; (d) the contribution of the course unit to the development of knowledge, skills, and attitudes; (e) the course unit's implications for overall learning; and (f) overall satisfaction with the educational experience. Responses will be recorded on a 5-point Likert scale, where 1 indicates "Not at all satisfied" and 5 indicates "Very satisfied". Students will also be presented with a final open-ended question: "At any point during the laboratory practice sessions (simulation), did participants experience any emotional discomfort (e.g., anxiety, restlessness, palpitations, nervousness, trembling, urinary urgency, fear, emotional lability) related to the pedagogical strategy employed? Please describe the participants' experience." To promote participant retention and ensure complete data collection, the following strategies will be implemented: (a) regular communication with participants, reinforcing the importance of their continued participation throughout the study; and (b) automated reminders sent via INFOREstudante prior to each laboratory practice session.

In cases where participants discontinue the intervention or do not fully adhere to the protocol, the following data will be collected: (a) baseline characterisation data; (b) outcomes from assessments completed up to the point of discontinuation; (c) documentation of partial participation in the intervention activities; and (d) the final satisfaction questionnaire (if the participant agrees to complete it), even if all planned stages have not been completed. Where possible, the reason for discontinuation or protocol deviation will also be recorded through direct contact with the participant. These participants will be classified as cases of: (a) non-adherence to the intervention or (b) non-retention in the study.

Data management Collected data will be entered into a secure electronic database. The following measures will be implemented to ensure data quality and integrity: (a) automated range checks to verify that entered values fall within expected limits; (b) standardised variable coding based on a pre-specified data management plan; and (c) periodic reviews by the research team to identify inconsistencies or missing data.

Data will be stored on password-protected servers with access restricted to authorised members of the research team. Data will be retained long term to enable future comparative analyses.

Statistical methods The primary data analysis will be conducted according to the intention-to-treat (ITT) principle, including all participants in the groups to which they were originally assigned, irrespective of their adherence to the intervention. This approach preserves the benefits of randomisation and minimises potential bias.

In addition, a secondary per-protocol (PP) analysis will be performed, including only participants who meet the pre-specified adherence criteria for the assigned educational intervention. This analysis will allow examination of the intervention's effects under ideal implementation conditions.

To compare the intervention and control groups, the following methods will be used. The primary outcome variables (ICAS and SE-12) will be analysed using repeated-measures models. For continuous outcomes (ICAS, SE-12), a linear mixed model (LMM) will be fitted with fixed effects for group (intervention vs control), time (categorical time points), and the group×time interaction, and with a random intercept at the participant level. The parameter of primary interest will be the group×time interaction term, which estimates the mean between-group difference in change over time. Results will be reported as the between-group difference in mean change with 95% confidence intervals and two-sided p-values (significance level: p < 0.05).

Models will preferably be estimated using restricted maximum likelihood (REML). Where appropriate, models will be adjusted for the baseline value of the outcome and for pre-specified covariates. If model residual assumptions are not met (e.g., non-normality or heteroscedasticity), the investigators will consider outcome transformations, the use of generalised linear mixed models (GLMMs) with appropriate family/link functions, or robust estimation approaches (e.g., bootstrap methods).

The secondary outcome (satisfaction at the end of the learning experience) will be summarised using means and standard deviations, with between-group differences analysed accordingly. For outcomes that are clearly ordinal (e.g., satisfaction measured on a Likert scale), a mixed-effects ordinal modelling approach will be considered. Mixed-effects models accommodate missing data under the missing at random (MAR) assumption; sensitivity analyses (e.g., multiple imputation and per-protocol analyses) will be conducted to assess the robustness of the conclusions.

As there are two primary outcomes, multiplicity will be addressed in accordance with the Statistical Analysis Plan (e.g., specification of co-primary endpoints with p-value adjustment using Holm/Bonferroni procedures, or hierarchical testing of outcomes). Model fit will be evaluated through diagnostic checks (inspection of residuals and assessment of influential observations) and, where necessary, additional random effects and/or appropriate correlation structures will be incorporated. Point estimates and 95% confidence intervals (95% CIs) will be reported.

Missing data are assumed to be missing at random (MAR), meaning that the probability of an observation being missing depends on observed variables but not on the unobserved (missing) value itself. This assumption will be examined based on the distribution of collected data and patterns of non-response. If there is evidence suggestive of missing not at random (MNAR), sensitivity analyses will be undertaken.

Missing data will be handled as follows: (a) for continuous variables (e.g., ICAS), multiple imputation using regression-based methods will be applied, incorporating relevant predictor variables; (b) for categorical variables, logistic-model-based imputation or, where appropriate, mode imputation may be used; and (c) imputation will be performed prior to the primary statistical analyses, and results will be compared with complete-case analyses to evaluate the robustness of the findings.

Multiple imputation helps preserve statistical power and reduces bias associated with excluding participants with missing data, and is recommended for studies of educational interventions in which missingness may arise for logistical or personal reasons. Sensitivity analyses will be undertaken to assess the robustness of results under different assumptions, including: (a) comparison of intention-to-treat and per-protocol analyses (restricted to participants who completed the intervention); (b) evaluation of the impact of alternative missing-data imputation methods; and (c) exclusion of participants with incomplete data or substantial protocol deviations.

These analyses will determine whether the main findings remain consistent across different analytical approaches, thereby strengthening the validity of the conclusions.

Data will be analysed using IBM SPSS Statistics, version 29. Data monitoring committee As this study evaluates an educational strategy and does not involve clinical risks or interventions with the potential for serious adverse effects, no Data Monitoring Committee will be established and no formal interim analyses are planned.

Trial monitoring No formal external monitoring plan is envisaged. Monitoring will be conducted internally by the research team through periodic reviews of data quality and protocol adherence.

Inclusion Criteria:

• active enrolment in the first year of the undergraduate Nursing degree programme
• first-time attendance of the Helping Relationship course unit.

Exclusion Criteria:

• None.