Background

The concept of the hidden curriculum (HC) in medical education has recently generated significant discourse among scholars and practitioners. However, there remains a lack of consensus regarding its ongoing relevance, the specific components that constitute it, and the degree of its influence on medical training. Further empirical investigation is warranted to deepen our understanding and contribute meaningfully to this ongoing dialogue (1). The HC in medical education addresses the implicit methods through which knowledge and behavior are shaped, functioning outside the boundaries of a medical school’s formal curriculum. It is especially significant due to the professional nature of the field, the diverse educational components, and the extensive learning environments, particularly in clinical settings. Essentially, the HC transmits the values, beliefs, and standard behaviors inherent in medical sciences(2, 3).

The definition of the hidden curriculum is currently a subject of debate. Some perceive it as encompassing the undesirable aspects of medical training, while others argue that it includes positive interactions and can be beneficial for both students and faculty (1, 4). The term “hidden curriculum” refers to the non-academic outcomes and by-products of education that are unexamined, covert, latent, unwritten, unplanned, and often invisible (5). Based on a definition, the HC represents a significant dimension of educational curricula, encompassing elements that extend beyond the formally established and informal curricula. Although unofficial, the HC can facilitate learning processes. In an alternative conceptualization, the HC is characterized by unarticulated expectations, unintended learning outcomes, implicit messages, and a curriculum shaped by students themselves. This encompasses the knowledge, ideas, perceptions, performance, and values that students acquire outside of their officially prescribed lessons. The impact of the hidden curriculum can result in enduring and influential educational outcomes (3). Hafferty has extensively explored the hidden curriculum in medical education, defining it as a collection of influences at both organizational and cultural levels. These influences encompass organizational policies, evaluation activities, resource allocation decisions, and intra-organizational policies (6, 7). Hafferty proposes that to uncover the hidden curriculum, one should examine four key phenomena: institutional policies, evaluation activities, resource allocation decisions, and institutional slang or nomenclature (8). The educational journey of medical students extends beyond the formal curriculum, encompassing a myriad of additional influences that shape their experiences and competencies. These influences, collectively referred to as the Hidden Curriculum, encompass a spectrum of values, behavioral norms, attitudes, skills, and implicit knowledge that students acquire throughout their training (9).

An examination of the scholarly literature in this domain reveals that a pivotal inquiry concerning hidden curricula in medical education pertains to their definition and the methodologies for measuring them using suitable and pertinent constructs. Consequently, various studies over the years have endeavored to delineate these elements and devise and validate appropriate instruments for their assessment.

Sarikhani et al. (9) identified ten primary components through a thematic content analysis approach, categorizing them into four distinct groups: structural factors, educational factors, cultural factors, and social factors. The sub-categories or main components of the hidden curriculum in medical education that they recognized are as follows: social factors, including student-instructor relationships, students’ interpersonal relationships, role modeling from instructors, and role modeling from clinical staff; cultural factors, including organizational culture and students’ cultural context. structural factors: organizational rules and structures, educational and clinical physical setting; educational factors: teaching methods, evaluation methods.

Pourbairamian et al. (6) identified the domains, impacts, factors, and components of the hidden curriculum in residency programs and proposed an initial conceptual framework. Through qualitative content analysis of selected studies, 55 codes were identified and categorized into seven themes and fourteen subthemes. The themes included organizational factors, sociocultural factors, professional factors, communication factors, educational factors, personal characteristics of residents, and educational characteristics of residents. Among these, educational factors and personal characteristics of residents were deemed most significant, while communication factors and educational characteristics of residents were considered least significant.

Yazdani et al. (5) employed thematic content analysis to capture the perspectives of key informants on the management of the hidden curriculum in medical education. Eleven interviewees contributed to the analysis, which identified five key themes: human resources, learning, organizational behavior, formal curriculum, and organization. The findings suggest that effectively managing these components can lead to better management of the hidden curriculum, enabling the planning of students’ education based on required and desirable performance outcomes.

Andarvazh et al. (10) used the McKenna method for concept analysis to define the hidden curriculum in medical education. Researchers reviewed 561 English and 26 Persian references, narrowing the selection down to 125 abstracts and thoroughly studying 55 articles. The hidden curriculum is defined as a powerful, intrinsic, and sometimes contradictory message embedded in an organization's structure and culture, conveyed implicitly through the learning environment by both structural and human factors. It includes cultural habits, norms, values, belief systems, attitudes, skills, desires, and social expectations, which can have both positive and negative effects. They concluded that the hidden curriculum contributes to reproducing existing class structures, socialization, and preparing learners for professional integration.

Rauf et al. (11) aimed to develop and validate a questionnaire to identify the characteristics of the hidden curriculum in medical education. Building on previous qualitative research, a panel of experts created a questionnaire, which was then verified through exploratory factor analysis (EFA) and quantitative methods. The initial 90-item questionnaire was refined to 39 items, and further validation resulted in a 33-item questionnaire with strong psychometric properties. The study identified three main factors of the hidden curriculum: accountability and equal opportunity, communication and stakeholder relationships, and student-centeredness and empowerment. These constructs collectively measure the hidden curriculum in medical institutes.

Studies show a lack of valid tools to measure the hidden curriculum in Iranian medical education. This study aims to develop a robust, locally validated instrument to address this gap. Specifically, this research investigates the factor structure of a 33-item questionnaire designed to assess the hidden curriculum in medical institutes, adopted from Rauf et al. (11), employing a confirmatory factor analysis methodology. Thus, this study represents a significant contribution to the field by examining, for the first time within an Iranian context, the factor structure and psychometric properties of the "Hidden Curriculum Questionnaire in Medical Institutes." This research provides the first validated instrument specifically designed to measure the hidden curriculum within the unique context of Iranian medical education. Additionally, by rigorously validating a tailored instrument, this study provides a novel and essential tool for future research on the hidden curriculum in Iran, addressing a previously unexplored gap.

This study validated the first- and second-order factor structures of the "Hidden Curriculum Questionnaire in Medical Universities" for Iranian medical education, demonstrating its reliability and applicability for assessing hidden curriculum components. The findings confirmed three first-order factors—Communication and Reform, Student Centeredness and Empowerment, and Accountability and Inclusiveness—while establishing The Hidden Curriculum as a second-order construct. Notably, student-centeredness and Empowerment played the most significant role. Despite the study's strong validity and reliability, it was limited to students from Kerman University of Medical Sciences, necessitating future research across broader populations and faculty perspectives to further refine the tool.

Objectives

Against this backdrop, the primary objective of this study was to investigate the factor structure of the Hidden Curriculum Questionnaire within medical universities.

Methods

Participants and Setting: The current study is descriptive and falls within the scope of evaluating the psychometric properties of a questionnaire. The statistical population consisted of students from Kerman University of Medical Sciences, totaling 5,086 individuals. A sample of 360 students was selected using the Krejcie and Morgan table, employing a proportional stratified sampling method across various faculties, including Health, Nursing and Midwifery, Medicine, Paramedical Sciences, Pharmacy, Dentistry, Iranian Medicine, and Medical Management and Information. Participants were selected from the research's statistical sample, with proportional allocation to each faculty. Upon arrival at each faculty, researchers engaged with available student groups in classrooms. Accordingly, some of the students in the classrooms were invited to participate in the study. The study protocol, including informed consent forms, data collection procedures, and measures to ensure participant confidentiality, was reviewed and granted formal approval by the Ethics Committee of Kerman University of Medical Sciences. Before the initiation of the study, all participants were comprehensively briefed on the research objectives, the confidentiality of their responses, and their right to withdraw from the study at any point. The anonymity of the participants was ensured throughout the implementation and analysis of the research data.

Measures: The primary instrument utilized in this research was the "Hidden Curriculum Questionnaire in Medical Institutes," which consists of 33 items (Appendix 1) and was developed and validated by Rauf et al. (11). This questionnaire encompasses three subscales: Communication and Reform, Student Centeredness and Empowerment, and Accountability and Inclusiveness. Respondents indicated their level of agreement with each item using a five-point Likert scale, ranging from "strongly agree" to "strongly disagree." Before administration, the questionnaire was translated into Persian. The process involved independent translation and back-translation by two translators. This multi-step process included forward and back-translation, reconciliation by the researchers, and cognitive debriefing through pilot testing to ensure conceptual, semantic, and cultural equivalence within the target context. The resulting English version was compared to the original, verifying that the essential meaning of all items was retained. Additionally, in accordance with ethical research standards, the confidentiality of participants' responses was explicitly stated in the distributed questionnaires.

Statistical Analysis: After conducting a screening for outliers and missing data, the total number of questionnaires included in the statistical analyses was reduced to 360. The collected data were subsequently analyzed using the Statistical Package for Social Sciences (SPSS) version 26 and Analysis of Moment Structures (AMOS) version 24 software. The instrument's reliability was assessed utilizing the internal consistency method within SPSS, where Cronbach’s alpha coefficients were calculated for both the overall scale of the instrument. All coefficients surpassed the critical threshold of 0.7 and were statistically significant, with the overall questionnaire achieving a Cronbach’s alpha of 0.94. Furthermore, the Cronbach’s alpha coefficients for the CR, SCE, and AI subscales were calculated as .87, .85, and .86, respectively, indicating strong internal consistency for each measure.

The analysis of the correlation coefficients among the various factors within the model, as well as their associations with the overarching construct of the hidden curriculum, reveals that all correlations among the model’s factors are statistically significant at the 0.001 level. Notably, the correlation coefficients between the total scale score and the individual components—Communication and Reform, Student Centeredness and Empowerment, and Accountability and Inclusiveness—are 0.930, 0.883, and 0.907, respectively. These values suggest a robust internal validity for the instrument.

To elucidate the construct validity and analyze the factor structure of the "Hidden Curriculum Questionnaire in Medical Institutes," as well as to assess the second-order factor analysis model, Confirmatory Factor Analysis (CFA) was conducted using AMOS software, employing the maximum likelihood estimation method. First-order confirmatory factor analysis (CFA) tests whether observed variables load onto their respective latent factors, thus confirming the structure of the measurement model. Second-order CFA extends this approach by evaluating whether first-order factors load onto a higher-order latent construct, providing insight into broader underlying dimensions. Essentially, first-order CFA focuses on direct relationships between observed variables and factors, while second-order CFA examines hierarchical relationships among multiple latent constructs to determine if they create a more general overarching factor.

Two categories of fit indices were utilized to evaluate the proposed research model. The first index considered was the chi-square statistic (χ²), which serves as a measure of goodness-of-fit; however, it is regarded as a "badness-of-fit" index, as higher values indicate weaker support for the theoretical model under examination (12). The application of the chi-square statistic necessitates data collection from a sample size ranging between 200 and 500 participants (13). In this study, a total of 360 completed questionnaires were analyzed, allowing for the appropriate use of the chi-square statistic to assess model fit. Furthermore, the ratio of the chi-square statistic to the degrees of freedom (CMIN/DF) was employed as an additional model fit index. This relative or normalized chi-square index is deemed acceptable when its value is less than three (14). Additional fit indices were classified into two groups: comparative and parsimonious goodness-of-fit indices. The Comparative Fit Index (CFI) and Tucker-Lewis Index (TLI) fall within the category of comparative indices (with the chi-square statistic also categorized among absolute fit indices). Values exceeding 0.95 for these indices are interpreted as indicative of an excellent fit, while values above 0.90 are considered acceptable (15). The parsimonious fit indices utilized in this analysis included the Parsimonious Normalized Fit Index (PNFI) and the Parsimonious Comparative Fit Index (PCFI), along with the Root Mean Square Error of Approximation (RMSEA). Generally, values above 0.5 are deemed appropriate for the first two indices. For RMSEA, a threshold of less than 0.06 is indicative of a very good model fit, while values below 0.08 are considered acceptable (15).

It is essential to note that, in addition to using these indicators to assess model fit, items with factor loadings below 0.5 were excluded from the model to enhance its conciseness, reliability, and validity. This threshold was selected based on established methodological guidelines in psychometric research, which suggest that factor loadings ≥0.5 (indicating at least 25% shared variance between the item and the latent factor) are considered practically significant for retaining items in a scale (16, 17).

While the use of a factor loading cut-off of 0.5 is a conventional and well-justified criterion for item retention, the psychometric robustness of the scale could be further strengthened by also evaluating items based on their contribution to the scale's internal consistency (e.g., corrected item-total correlation > 0.3) and the absence of significant cross-loadings onto other factors. This multi-faceted approach helps ensure the final instrument is both parsimonious and conceptually sound.

Results

Table 1 outlines the faculty-wise distribution of participants (N = 360), with Medicine predominating (41.6%), trailed by Health Sciences (13.0%), Paramedical Sciences (12.5%), Nursing and Midwifery (10.5%), Pharmacy (9.7%), Dentistry (7.8%), Medical Management and Information (4.4%), and Iranian Medicine (0.6%). Based on this Table, the study comprised a total of 360 participants, with females representing the majority (n = 218, 60.7%), followed by males (n = 142, 39.3%).

Table 2 presents the reliability of the measurement scale and the item-total correlations. The corrected item-total correlations range from 0.369 to 0.718, reflecting varying item-construct associations, with higher values indicating stronger contributions. Cronbach’s alpha remains stable (0.940–0.943) if any item is deleted, confirming high internal consistency unaffected by individual item removal. The scale means and variance analyses reveal response distribution patterns, with items such as q32 and q1 exhibiting notable variance.

Table 1. Demographic distribution of research participants by faculty and gender

Table 3 presents the fit indices associated with the factor model of the "Hidden Curriculum Questionnaire in Medical Institutes." The data indicate that all fit indices fall within the acceptable range, thereby validating the factor analysis model and confirming its suitability for the statistical population under study. The root mean square error of approximation (RMSEA) was calculated to be 0.057, which is below the conventional threshold of 0.08, indicating a good fit. Furthermore, the chi-square to degrees of freedom ratio (CMIN/DF) for this model was determined to be 2.159, reflecting an adequate level of fit. Moreover, the evaluation of additional fit indices reveals that the Tucker-Lewis Index (TLI = 0.90) and the Comparative Fit Index (CFI = 0.90) exceed the recommended benchmark, indicating a satisfactory model fit. The two parsimonious fit indices, namely the Parsimonious Normalized Fit Index (PNFI = 0.76) and the Parsimonious Comparative Fit Index (PCFI = 0.82), also surpass the criterion of 0.5, further affirming their adequacy. 

Table 2. Reliability and item-total correlation analysis

Table 3. Fit indices of hidden curriculum within the first- and second-order factor model in medical sciences universities

Table 4 and Figure 1 present the factor loadings for each parameter associated with the identified factors, along with the standard regression weights for each factor within the factor model. The data indicate that all parameters corresponding to the sub-factors of the model exhibit positive and statistically significant factor loadings in relation to their respective latent factors. However, following the initial application of the factor analysis model, parameters 1, 3, 7, 24, and 32 were excluded from the model because their factor loadings fell below the threshold of 0.5. These parameters were excluded to purify the measurement model, retaining only items with strong, statistically significant relationships to the underlying latent factors.

This Table also presents the fit indices associated with the second-order factor model of the "Hidden Curriculum Questionnaire in Medical Institutes." The data indicate that all fit indices fall within the acceptable range, thereby validating the factor analysis model and confirming its suitability for the statistical population under study. The root mean square error of approximation (RMSEA) was calculated to be 0.059, which is below the conventional threshold of 0.08, indicating a good fit.

Furthermore, the chi-square to degrees of freedom ratio (CMIN/DF) for this model was determined to be 2.232, reflecting an adequate level of fit. Moreover, the evaluation of additional fit indices reveals that the Tucker-Lewis Index (TLI = 0.90) and the Comparative Fit Index (CFI = 0.90) exceed the recommended benchmark, indicating a acceptable model fit. The two parsimonious fit indices, namely the Parsimonious Normalized Fit Index (PNFI = 0.75) and the Parsimonious Comparative Fit Index (PCFI = 0.81), also surpass the criterion of 0.5, further affirming their adequacy.

Table 5 and Figure 2 present the second-order factor loadings for each parameter associated with the identified constructs, along with the standard regression weights for each factor within the proposed model.

The findings indicate that all sub-factors of the model—namely, Communication and Reform, Student Centeredness and Empowerment, and Accountability and Inclusiveness—exhibit positive and statistically significant factor loadings corresponding to their respective latent construct, the Hidden Curriculum. Specifically, the factor representing Student Centeredness and Empowerment demonstrates the highest regression weight of 0.96 in relation to the latent factor of the Hidden Curriculum. In contrast, the Communication and Reform is associated with the lowest regression weight of 0.87 regarding its influence on the Hidden Curriculum latent construct. Furthermore, Accountability and Inclusiveness contribute to the elucidation of the Hidden Curriculum latent factor, exhibiting a regression weight of 0.94.

Table 4. Factor load and significance level of the parameters in the first-order factor model

^*p<0.001

Table 5. Factor load and significance level of the parameters in the second-order factor model

^*p<0.001

Discussion

Brown's typology (18) delineates four distinct categories of curriculum: the formal curriculum, encompassing published syllabi linked to curriculum policy documents, often referred to as the explicit curriculum; the enacted curriculum, which pertains to the curriculum that is delivered in practice; the hidden curriculum, which encompasses unintended learning experiences encountered by students; and the null curriculum, which consists of content that is absent from the formal curriculum yet ought to be included. According to this typology, the curriculum within educational institutions encompasses values and expectations that may not be explicitly articulated in the formal curriculum but are nonetheless assimilated by learners through their experiences in educational settings. Eisner (19) refers to this dimension of the curriculum as the implicit or hidden curriculum. This definition suggests that the hidden curriculum encompasses a range of issues, including social control, covert and unacknowledged activities, as well as the non-scientific implications of educational practices.

Based on the empirical evidence reviewed in this study, there is a lack of a suitable and standardized instrument to evaluate the status of the hidden curriculum in Iranian medical higher education. Such an instrument is necessary to assess the components and structural elements that define the nature and essence of the hidden curriculum within medical education. This study aimed to validate the first and second-order factor structures of the "Hidden Curriculum Questionnaire in Medical Institutes" within the Iranian context.

This measurement instrument, consisting of a
33-item questionnaire developed by Rauf et al. (11), was specifically designed to assess components of the hidden curriculum in Pakistan. The findings indicated that both the first and second-order factor models demonstrated a good fit, thereby establishing this instrument as a standard tool for evaluating various aspects of the hidden curriculum in Iranian medical education institutions. The analysis confirmed three first-order factors: Communication and Reform, Student Centeredness and Empowerment, and Accountability and Inclusiveness.

Additionally, the overarching construct of The Hidden Curriculum was identified as a second-order factor. These structural components are essential for effectively measuring the Hidden Curriculum Questionnaire in Medical Institutes. Notably, the dimension of Student Centeredness and Empowerment was found to exert the most significant influence on the hidden curriculum index. It shows that all factors were strong contributors, with Student Centeredness and Empowerment being the strongest roles in elucidating the hidden curriculum within medical education institutions. These findings align with previous research conducted by Neve and Collett (20), Yazdani et al. (5), Li et al. (21), Shakerinejad et al. (22), and Parekh et al. (23).

Furthermore, the results indicated that removing five items from the original instrument resulted in a refined questionnaire that retains essential constructs pertinent to the hidden curriculum, thus rendering it a suitable tool for measuring this phenomenon in Iranian higher medical education. However, it is important to note that the definitive application of this questionnaire and its proposed items should not be based solely on the results of this study.

The reliability analysis revealed satisfactory internal consistency for both the overall scale and its constituent subscales within the sample utilized. The Cronbach's alpha coefficient for the complete questionnaire was 0.94, with each subscale exceeding the critical threshold of 0.7. These reliability estimates are consistent with those reported in prior studies; Rauf et al. (11) reported an overall instrument reliability of 0.96, with subscale values above 0.80. In the Iranian sample, the reliability coefficients for each subscale ranged from 0.85 to 0.88.

The findings of this study have significant implications for educational practices in Iranian medical institutions by providing a validated instrument for assessing the hidden curriculum. This tool allows faculty and administrators to identify unintended influences on student learning, including social norms, institutional expectations, and covert educational practices. By recognizing these factors, educators can implement targeted reforms to enhance inclusivity, student empowerment, and communication within medical training. Practical changes could include revising teaching methods to promote active student engagement, integrating discussions on implicit biases in medical education, and establishing policies to address curriculum gaps. The tool enables administrators to monitor the impact of institutional practices on students’ professional development, ensuring a more transparent and equitable learning environment. Additionally, expanding its application across diverse medical institutions will provide further insights into the broader effects of the hidden curriculum, guiding future policy development in Iranian medical education.

Conclusion

Given the validation of the first and second-order factor structure of the “Hidden Curriculum Questionnaire in Medical Institutes” within Iranian higher medical education, it is recommended that scholars in medical education employ this instrument. Its validity and exceptional conciseness enhance its applicability in research on the hidden curriculum in medical education.

However, the study’s limitations include its restriction to students of Kerman University of Medical Sciences. Future research should therefore evaluate this instrument across a broader statistical population with diverse backgrounds. Additionally, the study’s statistical population comprised medical students from various scientific disciplines. Due to the limited number of these subgroups, it was not feasible to conduct comparative analyses for tool validation. Consequently, it is advised that this tool be administered to larger statistical samples to facilitate subgroup analyses. Moreover, it is suggested that future researchers develop and validate similar tools based on the constructs of this questionnaire to explore faculty members’ perspectives on the hidden curriculum in medical sciences. The utilization of this validated instrument enables institutions to quantitatively assess the hidden curriculum, thereby facilitating its strategic management to enhance student development and optimize educational outcomes.