In this study, we aimed, for the first time, to develop a tool that taps into learners’ readiness for both SRL and SDL through the comprehensive lens of the SR framework. SR primarily focuses on learners’ willingness and ability to recognise learning needs at any time, their awareness and confidence in addressing those needs, and their capacity to set goals based on those needs and take action to meet them [23].

The validation study of the proposed scale identified four factors related to SR in health professions students: ‘Inquisitiveness’, ‘Accomplishment’, ‘Implementation’, and ‘Independence’, all of which align with the core aspects of SR.

According to our main analysis, ‘Inquisitiveness’ explained the largest proportion of variance (31.17%) and was shown to be a reliable indicator of SR (Cronbach’s alpha: 0.860). This aligns with the conceptualisation of inquisitiveness as an intellectual virtue—with the common goal of improving one’s beliefs, knowledge, and understanding—while being uniquely characterised by a tendency to question [35]. An inquisitive individual is ‘characteristically motivated to engage sincerely in good questioning’ (p. 43) [35]. This definition closely aligns with that of a learner with high levels of SR, who is considered to be motivated by a desire to learn [23].

Inquisitiveness, in the context of learning, manifests as a purposeful curiosity, fostering reflection, critical thinking, and a continuous pursuit of knowledge [36]. To better contextualise this, curiosity—a sister concept to inquisitiveness—is defined as the ‘… desire for knowledge or information in response to experiencing or seeking out collative variables which is accompanied by positive emotions, increased arousal, or exploratory behaviour’ (p. 37) [37]. In this definition, collative variables refer to factors such as novelty, complexity, ambiguity, challenge, disequilibrium, and uncertainty [37]—many of which align closely with the items loaded on ‘Inquisitiveness’.

A closer examination of these items highlights their relevance to various aspects of curiosity. For instance, item SR 1 (‘I search for possibilities to learn new things’) and item SR 6 (‘I enjoy learning new things’) reflect ‘novelty’ as one of the aspects of curiosity, while item SR 14 (‘I welcome challenges in learning’) represents ‘challenge’ as a trigger for information-seeking. Furthermore, higher levels of curiosity are associated with greater intrinsic motivation to explore beyond merely fulfilling assessment requirements or meeting outlined expectations [38], a concept well captured by item SR 7 (‘I seek to learn beyond the stated requirement’).

Inclusion of items SR3 (‘I learn to improve myself’), SR4 (‘My reason for learning is to gain personal benefit’), and SR5 (‘I learn to satisfy my curiosity’) under this factor aligns closely with the interest-type (I-type) curiosity. I-type curiosity arises when individuals perceive learning something new as enjoyable or intellectually stimulating [39]. In contrast, D-type curiosity (deprivation-type) arises from recognising a gap in understanding that creates a sense of discomfort until resolved with new information [39]. While items SR3 and SR4 primarily reflect the I-type curiosity, they also hint at a sense of disequilibrium (i.e. a perceived gap). Specifically, inquisitive individuals may identify areas in themselves that need improvement (SR3) and see personal benefit in addressing this disequilibrium (SR4). Thus, both forms of curiosity influence how individuals approach new information, the SRL strategies they employ, and the way they set SDL goals [39].

According to the definition of SR, learners with high levels of SR will engage in SDL activities when they identify a learning gap [23], seemingly aligning more with D-type curiosity. However, considering the items loaded on ‘Inquisitiveness’, we propose that learners with high SR levels are not only capable of addressing their learning needs but also demonstrate an intrinsic desire to learn for its own sake. This disposition, although not always actively expressed, remains an enduring aptitude, reinforcing their identity as lifelong learners.

The term accomplishment is defined as ‘the action or fact of accomplishing something; fulfilment, completion; achievement, success’ [40]. In formal education, accomplishment of articulated learning goals is generally equated with student achievement [41]. However, in informal learning environments, which are central to lifelong learning, the determination of accomplishment largely rests with the learner, who assesses the extent to which they have achieved their learning goals [42]. Given this, in the context of SR, accomplishment will be defined as the success of learners in meeting their learning needs. This is well captured by most of the items loaded on ‘Accomplishment’ (SR25: ‘I complete my learning despite challenges’; SR26: ‘I meet my learning objectives’; SR27: ‘I meet my learning needs on schedule’; and SR28: ‘I meet my learning needs fully’).

From another standpoint, items loaded on ‘Accomplishment’ reflect learners’ confidence in themselves for meeting their needs—interpretable as self-efficacy—as well as awareness of their own capacity to do so, which aligns more closely with self-concept [43]. This is best represented by item SR9 (‘I am aware of my learning capabilities’). Traditionally, self-efficacy has been incorporated into SRL theories as an integral component of the learning cycle [5, 8]. Higher self-efficacy in learners is associated with a greater willingness to initiate challenging learning tasks, increased effort and persistence in implementing those tasks, and lower levels of anxiety [43]. Given this theoretical perspective, it is unsurprising that ‘Accomplishment’ emerged as the second major factor explaining SR aptitudes in health professions students. Consequently, learners who perceive higher levels of accomplishment are expected to demonstrate higher levels of SR.

Notably, the results of CFA showed a large covariance (0.69, Fig. 1) between ‘Inquisitiveness’ and ‘Accomplishment’. As discussed in the ‘Inquisitiveness’ section, inquisitiveness is essential for individuals to engage in learning independently, specifically involving active questioning. Considering this active questioning aspect, the relationship between ‘Inquisitiveness’ and ‘Accomplishment’ is logical, since active questioning would not occur if the learner did not believe in their ability to successfully complete learning tasks or lacked a sense of accomplishment.

Once a learner recognises the need for learning, the ‘Implementation’ phase begins, with formulating learning goals, identifying resources, choosing learning strategies, and evaluating the outcomes [7]. While SR, like SRL and SDL, views learning as a cyclical process [23], the steps are not necessarily sequential in every learning process. Each step is informed by other steps and influenced by components such as self-observation, self-judgement, and self-reaction [5]. Learners with high levels of SR are expected to monitor each step in their implementation, reflect on outcomes [44], and adapt their strategies accordingly [23].

The items loaded onto the ‘Implementation’ factor in our SR Scale clearly represent these steps, encompassing goal setting (SR 18: ‘I set my own learning objectives’), resource identification (SR 17: ‘To start learning, I organise relevant available learning materials’), adopting/adapting learning strategies (SR19: ‘I plan my learning in advance’), and monitoring (SR30: ‘I evaluate my learning’).

A moderate covariance was observed between ‘Implementation’ and ‘Inquisitiveness’ and between ‘Implementation’ and ‘Accomplishment’ (0.55 and 0.59, respectively; Fig. 1). This relationship, especially when SR is the focus, can be explained by the fact that learners need to be inquisitive, driven by a curiosity for learning, and have an adequate sense of accomplishment to initiate a learning process and implement their learning strategies [35, 43].

‘Independence’ explained 2.54% of the variance in our model, involving three items: ‘Ican find resources by myself’ (SR10), ‘I learn independently to other people’ (SR13), and ‘I attempt to independently solve learning challenges’ (SR21). These items represent different aspects of independent learning. According to Moore’s definition [45], independent learning occurs when learning takes place in a time and place separate from teaching, with the learner having an influence at least equal to the teacher, in setting goals, identifying resources, and making decisions for evaluation. Particularly, independence in learning is governed by distinct dimensions: time, place, pace, content, medium, technology, method, relationship, disclosure, and delegation [46]. It is important to emphasise that independence, neither in its definition nor as a factor explaining SR aptitudes, does not equate to learning alone and without any support. Indeed, in modern perspectives, while a learner can be totally independent of a teacher, their independence is multifaceted and constantly shifting. That is, they can delegate control in any of the aforementioned dimensions when needed and take it back when it is not [47].

To explain the moderate-to-large covariances observed between ‘Independence’ and all other factors (0.72 with ‘Accomplishment’, 0.66 with ‘Inquisitiveness’, and 0.40 with ‘Implementation’; Fig. 1), we again refer to Moore’s definition [45]. As independent learning occurs distantly from teaching, a lack of direct engagement with others might lead to a diminished sense of relatedness [47], which needs to be supported for intrinsic motivation to arise [48]. In this sense, we posit that learners’ innate inquisitiveness will, at least partially, fuel intrinsic motivation to mitigate the diminished sense of relatedness; hence, the observed relationship between ‘Independence’ and ‘Inquisitiveness’. Additionally, as the definition of independent learning emphasises learner autonomy [45], learners require sufficient confidence in their learning competence and a sense of accomplishment to make autonomous choices and take control of their learning [49]. Finally, referring to the definition of SR [23], we expect learners with high SR levels to independently initiate their learning and implement their learning strategies. Therefore, some degree of relationship between ‘Independence’ and ‘Implementation’ is expected. We emphasise that learners with higher levels of independence in learning, and by extension, higher levels of SR, are not necessarily independent in every learning context. Moreover, as Dron argues, ‘[t]here is no such thing as completely independent learning, at least in an educational context, because all learning depends on others, whether now or in the past’ (p. 62) [47].

Based on the results of the multiple groups invariance analyses, the SR Scale demonstrated consistent factor loadings across gender groups (Δχ2 = 24.982, Δdf = 16, p = 0.070) and courses of study (Δχ2 = 21.670, Δdf = 16, p = 0.154; see the ‘Multiple Groups Invariance Analyses’ section of ‘Results’). This indicates that the scale enables valid comparisons of relationships between latent constructs (i.e. ‘Inquisitiveness’, ‘Accomplishment’, ‘Implementation’, and ‘Independence’) and the final items, unaffected by demographic or field of study—at least within health professions.

Overall, our findings align with the theoretical perspective [9] that adult learners are inherently self-directed—albeit to varying degrees—and, by extension, possess some level of SR aptitudes. Consequently, we believe the SR Scale and the four-factor model proposed in this study may have broad applicability among adult learners.

It is believed that high levels of SR are essential for learners, particularly health professionals, to thrive as lifelong learners and demonstrate competence in professional practice [23]. As such, greater emphasis should be placed on developing these aptitudes in health professions education. The SR Scale provides a valuable tool for future research, enabling investigation of factors influencing SR aptitudes and informing the development of educational strategies aimed at nurturing and enhancing SR in learners.

A key limitation of this study is its focus on English-speaking countries. Although students from various backgrounds and health disciplines were included, the similarities in the educational systems of these Commonwealth countries may limit broader applicability. This highlights the importance of conducting further validation studies in more diverse educational settings.

This study used the entire sample for both EFA and CFA (n = 315). It is acknowledged that some researchers argue that performing CFA on the same sample used for model creation via EFA risks circular reasoning and overfitting [50, 51]. To mitigate this, they advise against conducting CFA as a follow-up analysis to EFA [28] and instead recommend performing cross-validation by creating subsamples, conducting EFA on one subsample, and CFA on the other [52, 53]. Others, however, suggest that a split-sample strategy may be less effective than the whole-sample strategy for evaluating the factor structure and is only viable for large samples [54]. Given the available sample size (n = 315), splitting the sample between EFA and CFA could have been counterproductive, as it would increase the likelihood of Type II error due to the insufficient sample size for a split dataset analysis. Additionally, in our study, the multiple groups invariance analysis demonstrated measurement invariance and stability of the factor structure across different populations. The use of bootstrapping for the CFA provided additional evidence supporting the stability of the factor structure [33].

Finally, while the total sample size was sufficient to establish validity and generalisability, there was a disproportionate number of female respondents. However, measurement invariance was established across genders, indicating that the imbalance did not affect the validity of the findings. Nonetheless, larger samples across different subgroups, particularly students from various health fields or academic levels, may further enhance the applicability of the findings.