Polish Adaptation of the Nurse Professional Competence Scale

Introduction

Nursing competence is a complex and multidimensional construct that encompasses not only theoretical knowledge and practical skills but also professional values, attitudes, clinical judgment, and interpersonal abilities [1]. It refers to the effective and ethical performance of nursing duties within a specific clinical context, while simultaneously adapting to the evolving demands of the healthcare system [2]. According to the World Health Organization (WHO), competence refers to observable capabilities of healthcare professionals that integrate knowledge, skills, and attitudes applied in real-world settings [3]. The WHO emphasizes that competencies should be developed to ensure comprehensive readiness for action, ranging from the provision of direct patient care to interdisciplinary collaboration and active involvement in public health and health promotion initiatives [3]. The International Council of Nurses (ICN) defines nursing competence as the effective application of a combination of knowledge, skills, judgment, and personal attributes necessary for the safe and ethical performance of nursing roles in specific contexts [4]. This definition highlights professional autonomy, clinical decision-making, and readiness to assume advanced practice roles such as Advanced Practice Nursing (APN) [4,5]. The American Nurses Association (ANA) describes competence as the expected level of performance that integrates knowledge, skills, abilities, and judgment grounded in evidence-based practice and clinical experience [6]. The ANA emphasizes the need for continuous professional development, stating that competence should not only be attained but also systematically updated throughout a nurse’s career [7]. A common denominator across these perspectives is the recognition of competence as a foundation of nursing professionalism and a key determinant of high-quality, safe, and person-centered care [8]. Therefore, nursing competence is not a static state but a dynamic developmental process [9], shaped by education, clinical experience, work environment, and health policy [10].

Assessing nursing competence across different healthcare systems is challenging, as educational structures, scopes of practice, regulatory frameworks, and workplace expectations vary substantially [11]. These differences lead to inconsistent definitions and operationalization of competence, while existing assessment tools differ in their conceptual foundations, structure, and psychometric quality, limiting meaningful cross-country comparability [12]. Together, these variations highlight the need for standardized yet culturally sensitive instruments that can accurately capture the complexity of nursing competence within diverse national contexts [12].

Nurses of the future are expected to play a pivotal role in managing systemic changes in healthcare and promoting population health. To meet these expectations, they must demonstrate high-level competence across all domains of professional practice [13]. Evidence suggests that a higher level of clinical competence correlates with lower hospital mortality rates, underlining the critical importance of systematically monitoring and developing nursing competencies [13,14]. Reliable instruments for assessing competence not only inform the refinement of nursing education programs but also support the design of targeted interventions in clinical practice [15–17]. As research indicates, it is essential to apply methods that reflect the unique nature of the caring sciences and can measure the core phenomena underlying professional nursing care [18–20].

In everyday clinical practice, nurses encounter multiple challenges, such as heavy workloads, time pressure, staff shortages, and rising professional accountability that can hinder the accurate assessment of competence [21]. Cultural norms, expectations regarding autonomy, and local organizational structures may further influence how nurses interpret competence items, affecting the reliability of assessment tools across different contexts [20,21].

The Nurse Professional Competence (NPC) Scale was originally developed in Sweden by Nilsson et al as a comprehensive instrument for assessing self-reported nursing competence [22]. Initially comprising 88 items, the scale has been extensively used in both national and international studies involving nursing students and practicing nurses [22]. In response to the need for a more practical yet psychometrically sound version, a short form (NPC-SF) was introduced in 2017, consisting of 35 items across 6 domains [23]. This validated instrument provides a reliable framework for evaluating core nursing competencies and is particularly useful for large-scale assessments in both educational and clinical contexts [24–26].

Although the NPC-SF has been used in multiple international contexts, its direct application in Poland may be limited due to cultural, educational, and regulatory differences [27]. The Polish nursing profession is undergoing dynamic transformation, including curriculum modernization, expanded scopes of practice, and ongoing work toward implementing Advanced Practice Nursing (APN). These developments increase the need for a validated, culturally appropriate competence assessment tool that reflects the Polish regulatory and educational environment [28]. Despite its international use, no validated Polish version of the NPC-SF currently exists. This is an important research gap, limiting the ability to monitor competence development, compare outcomes across institutions, and support workforce planning or APN implementation [1,28]. Cross-cultural adaptation requires a rigorous methodological framework forward and backward translation, expert panel review, cognitive interviews, and psychometric testing [20]. Validation must additionally assess content and construct validity and internal consistency reliability to ensure scientific robustness and applicability in the Polish context [22].

The aim of this study was to culturally and linguistically adapt the Nurse Professional Competence Scale (NPC-SF) to the Polish context and to evaluate its psychometric properties, including content validity, construct validity, and internal consistency reliability.

Material and Methods

ETHICAL CONSIDERATIONS:

The study adhered to the principles of the Declaration of Helsinki and received approval from the Bioethics Commission of the University of Rzeszów (Resolution No.1/12/2021, dated December 1, 2021). All participants were informed about the purpose and procedures of the study, the voluntary nature of their participation, and their right to withdraw at any time. Before accessing the online questionnaire, participants were required to provide informed consent, which was a mandatory condition for participation. The dataset was fully anonymized and contained no personally identifiable information.

STUDY DESIGN AND SAMPLE:

This psychometric study employed a cross-sectional design. The data were collected between late 2023 and early 2024 using an anonymous online survey. The survey link was distributed via regional nursing chambers as well as through closed social media groups and professional forums dedicated to registered nurses in Poland, where holding a valid nursing license is a prerequisite for group membership. This recruitment method ensured controlled access to the questionnaire and prevented participation by individuals not practicing the profession. The study used a non-probability sampling approach with controlled access. The survey link was distributed exclusively through verified professional channels (regional nursing chambers and closed groups requiring license verification), ensuring that only professionally active registered nurses could participate, although the final participation was voluntary and not controlled at the level of workplace or specialization. To reduce selection bias, recruitment was limited to established and verified professional organizations and closed groups requiring authorization. The final sample consisted of professionally active registered nurses, including early-career nurses enrolled in MSc programs who had already completed a bachelor’s degree, held a valid license to practice, and were concurrently employed in clinical roles.

SAMPLE SIZE AND POWER ANALYSIS:

To determine whether the sample size was adequate for the planned structural equation modeling (SEM), a power analysis was conducted using a dedicated SEM sample size calculator [29]. The tested model included 6 latent variables and 35 observed indicators. Following conventional guidelines, a moderate effect size (0.3), a significance level of α=0.05, and a power level of 0.80 were initially assumed, which yielded a minimum recommended sample of 232 participants. To verify stability, the analysis was repeated with a higher power level of 0.95, increasing the recommended minimum to 246 participants. The final sample of can measure 441 nurses exceeded both thresholds, ensuring sufficient power and stable parameter estimation for confirmatory factor analysis and SEM. According to benchmarks by Clark [30], Comrey [31], and others [32–34], samples larger than 400 are considered very good or excellent for psychometric and factor-analytic research. Thus, the current sample meets high methodological standards for structural modeling. The survey also included a sociodemographic section collecting information on gender, level of education level, healthcare facility type, and years of professional nursing experience.

INCLUSION AND EXCLUSION CRITERIA:

Participants were required to be professionally active nurses holding a valid license to practice, and performing tasks relevant to the scope of the NPC-SF, such as clinical decision-making, patient education, care planning, and interprofessional collaboration. This criterion applied both experienced nurses and early-career nurses who, despite being enrolled in master’s-level nursing programs, were simultaneously employed in clinical roles. Nurses working exclusively in administrative or academic positions without direct clinical were excluded. Individuals on long-term leave (eg, maternity, parental, or medical leave), or those not holding a valid nursing license at the time of data collection, were also excluded.

INSTRUMENT – NURSE PROFESSIONAL COMPETENCE SCALE-SHORT VERSION (NPC-SF):

The Nurse Professional Competence Scale-Short Version is a 35-item instrument designed to assess nurses’ self-reported professional competence. It was developed in 2017 by a consortium of researchers from 7 Swedish universities and university colleges, based on the formal competence requirements defined by the Swedish National Board of Health and Welfare and internationally accepted core competencies for nurses. The tool was originally intended for both graduating nursing students and practicing nurses, and its psychometric properties have been confirmed in multiple international studies [35–37].

The NPCS-SF is divided into 6 domains: Nursing care (5 items), Value-based nursing care (5 items), Medical and technical care (6 items), Care pedagogics (5 items), Documentation and administration of nursing care (8 items), Development, leadership, and Organization of nursing care (6 items). Responses are recorded using a 7-point Likert scale ranging from 1 (“to a very low degree”) to 7 (“to a very high degree”). Domain scores are transformed to a 0–100 scale in accordance with the original scoring instructions developed by the NPC Research Group. A higher score indicates a higher self-assessed competence level in the corresponding domain. Each domain demonstrated acceptable internal consistency, with Cronbach’s alpha values exceeding 0.70. The reliability values reported in the original validation studies ranged from 0.71 to 0.86, confirming the scale’s internal coherence. The scale takes approximately 10 minutes to complete and can be administered in both individual and group settings. It may be complemented with sociodemographic or contextual questions to facilitate deeper analysis of factors associated with competence. The NPC-SF has been translated into several languages (including English, Norwegian, Danish, and Chinese), and its adaptation procedures are documented in the official manual and methodological publications by Nilsson et al [22,23,38–41].

TRANSLATION AND CULTURAL ADAPTATION PROCEDURE:

Permission to conduct the linguistic and cultural adaptation of the scale was obtained from the original authors. The adaptation process was carried out in accordance with international standards [42–45], and followed the detailed guidelines proposed by Nilsson, Gardulf, and Lepp, as described in their article Process of translation and adaptation of the Nurse Professional Competence [39].

The process followed the recommended multi-step methodology to ensure semantic, idiomatic, experiential, and conceptual equivalence between the original and target versions. During the adaptation process, several linguistic and cultural challenges were identified, including terminology related to leadership responsibilities and patient education. These required additional expert consultation to ensure that the terms accurately reflected the professional context of Polish nursing. A multidisciplinary team (nursing researchers, methodologists, and linguists) supervised all adaptation stages to minimize individual translator bias and ensure cultural appropriateness.

Specifically, the adaptation process included the following 6 stages:

STEP 1:

Forward translation – Two independent forward translations were performed by bilingual translators with expertise in nursing terminology and health sciences. Their native language was Polish, and they had professional-level proficiency in English.

STEP 2:

Synthesis of translations – A consensus version was developed during a reconciliation meeting involving both translators and the research team. Semantic discrepancies and conceptual clarity were carefully discussed, leading to a single preliminary Polish version.

STEP 3:

Blind back-translation – The synthesized Polish version was then back-translated into English by a third bilingual translator who was blinded to the original version. This translator had no prior knowledge of the NPC Scale and had clinical experience in nursing.

STEP 4:

Expert panel review (content validation) – An expert panel composed of nursing scholars evaluated the original, translated, and back-translated versions of the NPC Scale. The review focused on assessing conceptual equivalence, cultural relevance, and linguistic clarity. Revisions were made where necessary to ensure semantic and contextual alignment between the original and the Polish version. This step also served as the foundation for conducting quantitative content validity assessment (Content Validity Index). Based on expert ratings and qualitative comments, a pre-final version of the Polish adaptation was developed, which was subsequently subjected to comprehensive psychometric evaluation.

STEP 5: Pre-testing and cognitive interviews – The pre-final version of the Polish NPC Scale was tested with a convenience sample of 12 registered nurses. Participants provided feedback on item clarity, terminology, and overall acceptability. Minor linguistic refinements were implemented based on this feedback. Habits of linguistic expression differ depending on the cultural context [46]. To prevent spelling and grammatical errors, the finalized Polish translation was proofread by the researchers.

STEP 6:

Psychometric testing – The final Polish version of the scale underwent confirmatory factor analysis (CFA) to assess structural validity and internal consistency reliability. The analysis confirmed the 6-factor structure of the original tool and yielded satisfactory goodness-of-fit indicators and Cronbach’s alpha values for all subscales.

No substantial cultural discrepancies were identified during the adaptation process. The original English version of the NPC-SF had already been translated with high linguistic and conceptual quality by the scale authors, and the competence areas it covers closely correspond to those defined in Polish nursing education and professional standards. Therefore, only routine semantic adjustments were required.

PSYCHOMETRIC ANALYSIS:

A comprehensive psychometric evaluation of the newly translated, culturally adapted, and cross-validated Polish version of the NPC-SV scale was conducted using a sample of the target population. The psychometric testing included: content validity assessment, construct validity assessment, and reliability analysis.

CONTENT VALIDITY:

Content validity assessment of the scale was assessed by a panel of 12 nurses with academic and clinical nursing experience, proficiency in English, and knowledge of research methodology. Following initial screening, 9 experts were retained for analysis, based on completeness and quality of their ratings. Each item was evaluated using a 4-point relevance rating scale (1=not acceptable (major revisions required); 2=needs significant improvement; 3=acceptable (minor revision needed), and 4=exceeds expectations (no revision needed). The experts paid particular attention to clarity of language, cultural relevance, and semantic and conceptual consistency. The I-CVI (Item-Level Content Validity Index) was computed for each item as the proportion of experts who rated the item as either 3 or 4. All items achieved I-CVI values ranging from 0.78 to 1.00, meeting the commonly accepted minimum threshold of 0.75 [47]. The S-CVI/Ave (Scale-Level Content Validity Index-Average method), was calculated as the average of all I-CVI values, was 0.94, indicating strong overall content validity of the instrument.

CONSTRUCT VALIDITY:

Construct validity was assessed using confirmatory factor analysis (CFA). To evaluate the model fit, several recommended indices were used, including the Comparative Fit Index (CFI), Tucker-Lewis Index (TLI), Root Mean Square Error of Approximation (RMSEA), and standardized root mean square residual (SRMR). The obtained values were: CFI=0.992, TLI=0.991, SRMR=0.065, and RMSEA=0.112. According to the 2-index guideline proposed by Hu and Bentler [48], model fit is considered acceptable if SRMR <0.09 and at least 1 of the following is met: CFI >0.96, TLI >0.96, or RMSEA <0.06. In this study, both CFI and TLI exceeded 0.96, and SRMR was below the recommended threshold, which supports the conclusion that the model demonstrates good overall fit. Despite the RMSEA exceeding the optimal level, the combination of high incremental fit indices (CFI, TLI) and acceptable residuals (SRMR) supports the structural validity of the scale.

RELIABILITY:

The internal consistency reliability of the Nurse Professional Competence Scale-Short Form (NPC-SF) was assessed using Cronbach’s alpha coefficient for each of its 6 subscales. The results demonstrated excellent internal consistency, as all alpha values exceeded the commonly accepted threshold of 0.70. The coefficients were as follows: Nursing Care – α=0.933; Value-based Nursing Care – α=0.959; Medical and Technical Care – α=0.901; Care Pedagogics – α=0.956; Documentation and Administration of Nursing Care – α=0.964; and Development, Leadership and Organization of Nursing Care – α=0.903.

These values indicate a high degree of internal coherence among the items within each subscale, suggesting that the translated version of the NPC-SF scale maintains strong psychometric reliability across all assessed competency domains. Values above 0.70 are generally considered indicative of acceptable internal consistency reliability. This threshold is consistent with the psychometric guidelines proposed by Nunnally and Bernstein [49], and Tavakol and Dennick [50] and is widely supported in the healthcare instrument validation literature.

STATISTICAL ANALYSIS:

All statistical analyses were performed using R software, version 4.4.1 [51]. The level of statistical significance was set at p<0.05. No missing data were detected; therefore, a complete-case analysis was applied. To evaluate the internal consistency of each subscale of the Nurse Professional Competence Scale-Short Form (NPC-SF), Cronbach’s alpha coefficients were calculated along with 95% confidence intervals (CIs). In addition, McDonald’s omega (ω) was calculated to obtain a more robust estimate of internal consistency based on CFA-derived factor loadings. To assess structural validity, confirmatory factor analysis (CFA) was conducted using diagonally weighted least squares (DWLS) estimation, which is appropriate for ordinal data.

The CFA results included standardized factor loadings, which were used to evaluate the strength of the relationships between items and their respective latent constructs. All factor loadings were statistically significant at p<0.001. Model fit was assessed using the following indices: Comparative Fit Index (CFI), Tucker-Lewis Index (TLI), root mean square error of approximation (RMSEA), and standardized root mean square residual (SRMR). All analyses were conducted using the freely available R software environment and standard functions from widely used packages ensuring transparency and replicability [51].

Results

PARTICIPANT CHARACTERISTICS:

A total of 441 nurses completed the survey in this study. Most respondents were female. Detailed characteristics of participants’ social and demographic information are presented in Table 1.

CONTENT VALIDITY:

The Item-Level Content Validity Index (I-CVI) values ranged from 0.78 to 1.00, exceeding the recommended threshold. The Scale-Level Content Validity Index/Average (S-CVI/Ave) was 0.94, indicating strong content validity of the Polish version of the NPC-SF.

CONSTRUCT VALIDITY:

The results demonstrated satisfactory values for the fit indices RMSEA, CFI, TLI, and SRMR. These values meet the criteria of the two-index strategy proposed by Hu and Bentler [48], which states that a model can be considered well-fitting when SRMR <0.09 and at least 1 of the following conditions is met: CFI >0.96, TLI >0.96, or RMSEA <0.06. The model acceptance followed the 2-index strategy, which allows the model to be considered adequately fitted even when RMSEA exceeds 0.06, provided that the CFI and SRMR meet the required criteria (Table 2).

INTERNAL CONSISTENCY:

Standardized factor loadings for the NPC-SF items ranged from 0.604 to 0.943, all statistically significant at p<0.001. Each subscale demonstrated high internal consistency, with factor loadings for individual items falling within acceptable to excellent ranges. In addition, McDonald’s omega (ω) was calculated as a more robust estimate of internal consistency; the overall ω value was 0.99, indicating excellent reliability. The lowest loading (0.604) was observed in the Medical and Technical Care subscale, while the highest (0.943) was found in Care Pedagogics. Although the loading for item 12 (0.604) is lower than for the remaining items, it still falls within the acceptable range for factor loadings in validation studies, and the item was retained to preserve the integrity and comparability of the original subscale (Table 3).

Discussion

STUDY LIMITATIONS:

This study has several limitations that should be acknowledged. First, the absence of a test–retest reliability analysis limits the ability to assess the temporal stability of the NPC-SF-PL. While internal consistency was found to be excellent, the consistency of scores over time remains unverified. Second, participants were recruited primarily through online channels, including professional forums and social media groups. Although eligibility was carefully controlled, online recruitment methods may limit the representativeness of the sample, particularly in terms of geographic diversity and digital literacy. Third, no subgroup comparisons were conducted, such as between different education levels, healthcare sectors, or seniority levels. These analyses could have yielded valuable insights into how competence profiles vary across segments of the nursing workforce. Similar limitations have been noted in prior validation studies. For example, Zaitoun [23] and Raiesifar et al [13] reported the need for longitudinal testing and broader sampling to improve generalizability. In addition, Nilsson et al highlighted the importance of comparing results across diverse demographic and clinical subgroups to identify disparities in perceived competence [20,22]. The study shares some methodological limitations typical for validation research. The reliance on self-reported data may introduce subjective bias. Construct validity was examined using CFA, and future studies could complement these findings with additional approaches such as convergent or discriminant validity. The RMSEA value was higher than optimal thresholds, a finding not uncommon in complex multidimensional models and DWLS estimation and should therefore be interpreted within this context. Overall, these limitations indicate directions for further research rather than weaknesses of the present study.

IMPLICATIONS FOR FUTURE RESEARCH:

Several avenues for future research emerge from the current study. First, it is recommended to conduct a test–retest reliability analysis to assess the stability of NPC-SF-PL scores over time, particularly in settings where the tool is used to monitor competence development longitudinally. Second, future studies should explore the use of NPC-SF-PL among broader groups of nurses, such as clinical nurse specialists, nurse educators, and nurses in advanced practice roles. This would enhance the tool’s generalizability and validate its use in specialized nursing domains. Third, researchers are encouraged to compare NPC-SF-PL outcomes with other validated nursing competence instruments to evaluate convergent validity. Instruments such as the PROFFNurse [62] or Nursing Competency Inventory could be employed to cross-validate findings and explore the multidimensional nature of professional nursing competence [63].

In summary, the Polish adaptation of the Nurse Professional Competence Scale-Short Form (NPC-SF-PL) demonstrated strong psychometric properties, including excellent internal consistency, robust factorial validity, and high content validity confirmed by expert review. The instrument retained the original 6-domain structure and proved to be both theoretically sound and contextually relevant for use in the Polish nursing environment. Beyond its psychometric strength, the NPC-SF-PL provides a standardized and practical tool that can be implemented in clinical, educational, and managerial settings to assess nurses’ competence profiles, identify development needs, and inform targeted professional training. The validated tool may also support evidence-based workforce planning, quality improvement initiatives, and educational reforms aimed at strengthening nursing competence in Poland. Its use is particularly relevant in the context of the ongoing expansion of nurses’ professional rights and the progressive introduction of the Advanced Practice Nursing (APN) role. By enabling systematic monitoring of competence levels, the NPC-SF-PL can facilitate the design of tailored educational programs and contribute to the effective integration of advanced nursing roles within the healthcare system.

Conclusions

The Polish adaptation of the Nurse Professional Competence Scale-Short Form (NPC-SF-PL) demonstrated strong validity and reliability, confirming its suitability for assessing professional nursing competence in Poland. The tool preserved the theoretical structure of the original instrument and enables comprehensive evaluation of core competence domains. Its availability supports both educational and clinical applications, offering a valuable resource for monitoring competence development and informing initiatives aimed at strengthening nursing practice. Future studies may additionally compare the NPC-SF-PL with other competence assessment instruments to further highlight its strengths and explore its applicability across different demographic and clinical groups.