## 2 Literature Review
### Hypotheses Derivation from Exploratory Studies  
In a recent study, [PERSON] et al. [15] reviewed 381 BIM-related articles between 2009 and 2015, and found that BIM adoption and implementation barriers ranked first amongst nine other BIM categories in the top 100 most cited publications, totaling 25 articles. This may be attributed to the rapid changes in BIM, which impose a knockout effect on knowledge patterns [25]. While a wide variety of knowledge sources exist from specialised professional institutes, including UK BIM Framework, BSI, NBS, Professional Bodies, CIC and HM UK Government, BIM Task Group, UK BIM Alliance, BIM4 Community Groups, Centre for Digital Built Britain (CDBB), etc., BIM users appear disoriented and to lack guidance on knowledge sourcing. Hence, 71% of industry professionals in the UK are reliant upon colleagues for BIM information, and the average are confident in their BIM knowledge and skills is 54% compared to 55% in 2017 [26]. These figures suggest that the BIM community is currently recycling available knowledge rather than actually improving it. [PERSON] et al. [13] similarly raised the same issue and recommended the ongoing training of employees to keep pace with the continual development of BIM knowledge. However, it is arguable that this type of information may simply be acquired by introducing users to their local BIM Body of Knowledge (BOK), which should incorporate information pertaining to BIM standards, practices, principles, and implementation processes for the profession. On the other hand, as the lack of in-house BIM skills/expertise remains one of the most influential barriers to BIM adoption, NBS [3] reveals a serious deficiency in BIM user competency. Although many HEIs and other educational institutes are integrating BIM education and training in their curricula, albeit to varying degrees, the AEC industry--both in the UK and worldwide--is still experiencing a lack of educated, BIM-competent employees [20]. This is attributed to the fact that the majority of educational institutes are focused on training and teaching BIM software technology for drafting despite a strong need for other nontechnical competencies [18; 19], which include aspects of BIM implementation, coordination, and management. [PERSON] et al. [20] share a similar view, adding that the acknowledgement of BIM competency will consolidate the missing constructs of knowledge, skills, and experience, which are sought by employers. Whereby, 'BIM Competency' refers to knowledge, training, and continuing professional development as a set of constructs measurable against performance standards and policies [27]. Accordingly, a BIM-competent user is regarded as an individual possessing BIM uptake (adoption and implementation) knowledge and expertise. Therefore, WBET may be understood as an organisational planned decision to invest in human capital for the purpose of leveraging employee-BIM competency. However, until HEIs and other educational institutes have developed curricula that shape BIM-competent mindsets, which is yet to be resolved [28; 29], it is only wise for organisations to invest in their own WBET programmes. Accordingly, two variables were identified in this section, 'Knowledge Acquisition' and 'User Competency'. According to [PERSON], et al. [30], both variables are derived from the 'Perceived Behavioural Control' construct, which reflects the impact of constraints on behaviour encompassing resource facilitating conditions and self-efficacy. Arguably, 'Knowledge Acquisition' and 'User Competency' may be regarded as external variables influencing 'Behavioural Intention to Use' following the standard path of TAM through 'Perceived Ease of Use'. Hence, provided there are adequate knowledge and skilled resources, it should be easy for an employee to use and control a new system. Therefore, since the term 'User Competency' encompasses knowledge and skills, it may be argued that 'Knowledge Acquisition' leverages the 'Behavioural Intention to Use' via 'User Competency'.