The construction industry plays a vital role in growing the US economy, accounting for approximately 4.2% of GDP [1]; however, it is widely recognized that the industry is experiencing a long-term shortage of skilled workers, which thus hampers its sustainability and growth ^[2][3][4][2,3,4]. According to the Association of General Contractors of America (AGC), 80% of general contractors have experienced difficulties in hiring sufficient craft workers to match the level of demand [5]. Previous research has documented and emphasized the shortage of skilled workers, and consequently, a loss in terms of productivity, growth in hourly wages, an increase in schedules overrunning, a decline in performance quality, and an increase in safety-related incidents in the construction industry [6].

The shortage of skilled labor has emerged as the US construction industry confronts difficulties in finding qualified craft professionals to meet the increased demands for employment in the industry ^[7][8][7,8]. McGraw described the labor shortage in the construction industry in terms of the problems surrounding recruiting and retaining skilled craft workers [9]. In addition to the labor shortage, other employment problems include the lack of craft competency among workers in the current workforce [10]. Existing workers in the construction industry have skill gaps, particularly with regard to soft skills such as communication and leadership, that prevent employees from performing tasks at a higher proficiency level ^[9][11][9,11].

The US construction industry is primarily built upon its highly skilled workforce. It requires individuals to possess a wide-ranging skillset, comprising soft skills, highly technical skills, and the ability to hold specialized roles ^[11][12][11,12]. In addition to possessing a diverse range of skills, workers in the US construction industry are also expected to adapt to rapidly evolving technological advancements, such as the use of drones, automation, and robotics [13]. The required combination of these skills is what makes the US construction industry require a highly skilled workforce [6].

The skillset of construction industry employees is defined in terms of the skilled workers’ knowledge, ability, and competence to perform specific tasks effectively in a wide variety of work situations ^[14][15][14,15]. Shah and Burke defined a skill as “an ability to perform a productive task at a certain level of competence” [16]. Nasirian et al. described skill levels in the construction industry in terms of a skillset held by workers that is at a level desired by the employer [14]. Within the construction industry, a skilled craft project is typically carried out by someone who works as a team leader and who utilizes their expertise in order to plan and execute the work in accordance with their independent judgement, while also overseeing and supervising team members [17].

Technical, socioemotional, practical, and cognitive skills, for example, have been identified as important skills that are required in the construction industry as they increase competency among craft professionals [18]. These skills are needed for the survival and growth of the workforce in the construction industry [19]. Some of these skills require a certain set of competencies in order to enhance workforce efficiency on site [20].

Craft competency refers to an individual’s ability to perform tasks that result in effective and excellent work performances when undertaking a job [21]; however, an individual’s competency, traditionally, is dependent on the organization’s work culture [22], a process of continuous improvements, as well as the individual’s measurable knowledge and skills [23]. These craft skillsets are distinguished from others by their perceived desirability in the construction industry [24]. Authors previously distinguished between craft skills and craft competencies by defining a craft skill as the ability of individuals to make use of specific tools for an intended purpose; this allows them to perform a specific task. Conversely, competency is defined in terms of the abilities, commitments, knowledge, and skills that enable individuals to perform jobs effectively in a wide range of working situations ^[15][17][15,17].

Recent studies comprehensively reviewed more than 260 articles to identify desirable skillsets among construction professionals. These studies found 72 skills that came together to form major competencies needed in the current construction industry market [19]. Among the identified 72 skills, organization, technical skills, human relations, communication, personnel management, and operational planning were identified as the most valuable skills in the construction industry, which is currently experiencing labor shortages [24]. The construction workforce may acquire some of these skills as they become more experienced; in other words, individuals in the workforce accumulate and develop these skills over time [25]. However, a gap exists between the workforce and the acquisition of these skills; this is attributed to the low competency level of workers [17].

To effectively enhance the competencies of construction craft workers, several training programs have been implemented using different strategies, resulting in improving the practical skills of the trainees [18]. These programs are generally associated with higher labor costs and training expenditures [26]. The multiskilling strategy is an alternative and appropriate solution to fill the skills gap and enhance competency levels ^[2][27][2,27]. According to scholars of strategic human resource management, the multiskilling strategy was introduced to the construction industry as a labor practice to build core competencies among craft professionals [28]. In general, the core competencies of multiskilled craft workers differ from one another [17]. These core competencies consist of skill sets that are developed through a variety of techniques that make multiskilled craft professionals capable of performing a variety of tasks [29]. They also consist of proficiency levels that measure the extent to which the individual is skilled in his or her craft [30]. Multiskilled craft workers are trained in multiple skills and competencies so they may master one or more skills in addition to their core competency skill ^[31][32][31,32]. However, a limitation in the existing literature is the absence of an examination of the impact of multiskilling strategies on craft competency. This rpapesearchr will focus on measuring the ability of the multiskilling strategy to enhance craft professionals’ competency in the construction industry. The Tier II strategy was developed to provide a structure for a long-term evaluation on an improved workforce [33]. The strategy could assess the workforce competency by measuring different skill levels identified by Tier II [34]. Subsequently, a survey was designed based on the Tier II workforce management strategy and administered among the U.S. construction industry workforce. The main objective of the rpapesearchr is to determine if the multiskilling strategy could enhance an individual’s competency in the construction industry. To address this primary objective, two secondary objectives emerge: (1) compare the strategy metrics in two Tier II components—craft technical and management skills between single-skilled and multiskilled individuals; and (2) explain the variability in both the project craft technical and project craft management Tier II score.

2. Workforce Competency

In most leading economies, the concept of workforce competency is commonly perceived and prioritized as a critical factor for economic growth ^[35][48]. For example, research conducted in New Zealand indicates that although the construction industry is one of the biggest employment sectors, it is currently facing a significant labor shortage, thus affecting the competitiveness of its construction workforce ^[36][49]. Regarding the UK construction sector, many companies are struggling with the challenge of retraining their workforce to adapt to new technologies or working methods due to a lack of skilled and competent workers ^[37][50]. Within the US construction industry, the US ranks third globally in terms of workforce competitiveness, behind Switzerland and Singapore ^[38][51]. Competency-modeling approaches that evolved from the original work of David McClelland in the late 1860s were proposed as effective models to identify the variables that predict successful job performance ^[39][52]. In 1998, Marrelli defined competencies as measurable individual abilities, commitments, knowledge, and skills that are required for effective work performance ^[40][53]. The term competency was broadly introduced to the management field by Boyatzis, who first introduced the “Job Competence Assessment” method in the USA ^[41][54]. Spencer and Spencer expanded on this definition to include “a motive, trait, skill, aspect of one’s self-image or social role, or a body of knowledge which he or she uses” ^[41][42][54,55]. In the late 1990s, the concept of competency has been studied and investigated by many researchers who later developed several competency models to analyze the performance of construction workers [17]. The study of workforce competency has been extended by numerous researchers to measure the impact of competent and incompetent workers’ activities in the construction industry. Durdyev et al. applied the structural equation model to identify the factors affecting construction labor productivity and they found a significant correlation between individuals’ competency and enhancing labor productivity in the construction industry [10]. Heravi and Eslamdoost proposed a predictive model for estimating construction workforce productivity ^[43][56]. They discovered that by enhancing “workforce competence,” workforce productivity could be increased by 13–18.7%, which makes it one of the most influential elements that can significantly improve labor productivity. In addition to productivity, workforce competency also plays a significant role in achieving a positive safety climate ^[44][57] and improved work performance in the construction jobsite ^[45][58], which leads to lower labor cost, and higher project quality ^[46][59]. Dai et al. identified superintendent competency and foreperson competency to be among the most influential factors that were related to construction industry workforce issues ^[47][60]. The most recent study by Johari et al. reported that higher competencies among the construction workforce can produce an effective and efficient work performance at the jobsite [17]. Several studies have been conducted in the past to develop models that measure the workforce competency level within the construction industry. Manoharan et al. focused on individuals’ competencies (KSAs) which are measurable; this included the level of significant knowledge, skills, and abilities that are required by the workers for effective work performance and for developing a labor training guide model that enhances the productivity and performance of a workforce in the construction industry ^[45][58]. In 2019, the Employment and Training Administration (ETA) collaborated with the Associated General Contractors of America (AGC) to promote a safe and skilled workforce with a program for developing higher competency levels and skillsets using models that are essential for educating and training a globally competitive workforce. This demonstrated that competencies are necessary for workers to enhance their efficiency at the jobsite [17].

3. Multiskilling Strategy

In recent years, the skilled labor shortage is considered to be the most critical issue facing the construction industry [3]. It is one of the major restraints on workforce productivity ^[48][61]. Multiskilling or cross-training has been proposed by the Construction Industry Institute (CII) and the Centre for Construction Industry Studies as one possible solution to reduce a shortage of skilled craft workers ^[49][44]. The multiskilling strategy refers to the training of the workforce in order to acquire different skills and tasks in different trades, in addition to their primary trade in the workplace ^[50][62]. The strategy brought more flexibility to human resources by assigning different tasks to workers during projects, which resulted in the alleviation of the skilled labor shortage problem ^[51][37]. Multiskilled crafts may have a primary trade where they are certified and highly competent, but their work is not limited to that trade ^[52][42]. The main motivation for introducing the multiskilling strategy to the construction industry was to enhance productivity and deal with workforce shortages ^[49][44]. The strategy has contributed to the construction industry’s development by reducing the lack of skilled labor ^[49][53][54][44,63,64], minimizing construction costs ^[49][44], increasing flexible staff deployment ^[54][55][56][41,64,65], improving onsite safety ^[51][37], and improving project quality ^[54][64]. The multiskilling strategy was introduced to the construction industry as a managerial strategy to develop competency within the workforce ^[49][44]. Duray addressed managerial issues through a survey and found that if workers were competent and multiskilled, this led to more flexibility in the workforce [27]. However, Gomar et al. believed that the benefits of multiskilling became insignificant after craft workers performed work in more than two trades ^[57][66]. Regardless, it is noteworthy to observe the impact of the multiskilling strategy on workforce competency.

4. The Tier II Workforce Management Strategy

Previous research has shed light on desirable skill levels among construction workforces. Construction workers are required to possess certain skill levels, defined as competencies, and these include, but are not limited to, problem-solving, communication, experience, people management, project management, and general computer skills ^[58][67]. The Tier II workforce management strategy will be applied to measure the presence of these skills among workforces in the construction industry. The Tier II workforce management strategy was introduced to the construction industry as a comprehensive method that formed part of a two-tier strategy that was proposed by the Center for Construction Industry Studies (CCIS) and the Construction Industry Institute (CII) [34]. The purpose of the Tier II strategy was to provide a structure for the long-term evaluation of workers, which could thus create an improved workforce [33]. Additionally, the Tier II strategy was adopted as a cohesive way of maximizing the utilization of the existing construction workforce, and to assess the potential impact of the lack of skilled construction labor by evaluating solutions to the problems of training, career paths, and wages in the industry ^[59][68]. The strategy also could measure the competency levels among the construction industry workforce [34]. The Tier II strategy is concentrated on the utilization of fewer, well-educated, and highly qualified craft professionals who also perform lower-management functions in addition to their primary duties in the workplace ^[60][69]. A key advantage of the strategy is to minimize construction cost, improve safety, improve project quality, and enhance both project schedules and productivity [34]. The characteristics of the Tier II workforce strategy is defined by metrics that measure the degree of implementation of the five index components: Project Craft Technical Skills, Project Craft Management Skills, Information Technology Utilization, Craft Utilization, and Organization, as shown in Table 1. The maximum score for each component is 100 points, and when divided by 50, it results in a maximum potential index score of 2.0 points per index component. Therefore, the Tier II Project Index can be calculated by adding up the scores of all five components. Forty percent of the Tier II Project Index score is composed of project craft technical skills and project craft management skill components, which are the two components that were included in this study. In 2005, Castañeda et al. indicated that the Tier II strategy metrics are feasible and achievable in assessing the proficiency of construction workers with regard to the skills proposed by the Tier II strategy [34]. In the Tier II matrix, proficiency is defined as a skill that renders workers competent and capable with little or no supervision ^[61][70].