2.1. Construction Delays in Global Context
From a global perspective, attempting to investigate or classify the various causes of delay in construction projects can seem daunting because the causes of delay can seem inexhaustible in the literature. For example, a study found up to 1057 causes from 47 peer-reviewed articles and concluded that 80% of these delays can be subdivided into three main categories: issues that arise at the execution stage, issues due to project administration, and issues related to labor disputes [
14]. In another study, an exhaustive catalogue of the roots of construction project delays (CPD) was carried out through a systematic review of studies spanning three decades (1985 to 2018), leading up to 97 selected studies, from which 149 causes of CPD were extracted [
15]. Findings showed that inadequate scheduling is a top-ranking cause of delay for both industry and academia, but one of the key gaps identified by this study is that there is need to investigate the inter-relationship (and reciprocal impacts) between several causes of delay. This is an interesting gap that this current study expects to fill. Furthermore, this study revealed that KSA was ranked 5th in the top 10 countries with research papers in this topic, and one of its top institutions—King Fahd University of Petroleum and Minerals (KFUPM)—was ranked as the top institution with the most papers. This suggests the importance that has historically been attached to research on construction project delays in KSA [
15]. A more recent review of the historical causes of delay examined 168 studies done between 1982 and 2021 and found that six major themes emerged in construction delay research: the framework for analyzing delays, a dynamic building information modelling (BIM) 4D-BIM based analysis of delays, new models for delay analysis, the selection of methods for delay analysis, critical chain management, and blockchain/smart contracts in delay management [
16].
Country-specific studies of the factors behind construction delays tend to provide a more manageable list. For instance, in Morocco, the top-10 reasons for delay were ranked in decreasing order of importance as follows: delayed progress payment, deficiency in training for workers, the absence of a management plan for construction waste, an unfeasible project duration, errors leading to re-work, the overuse of subcontracting, the delayed issuance of permissions from government, inadequate planning/scheduling, and uncoordinated planning and unskilled labor [
17]. A study covering 37 construction companies in Pakistan, and which ranked the sources of construction delay, placed them in this order: (1) contractor, (2) owner/client, (3) consultants, (4) materials, and (5) equipment [
18]. In Oman, it was found that client-side construction project delays are caused primarily by changing the scope of works, slowness of decision making, poor communication with stakeholders, and delayed progress payments [
19].
Some delays are caused by supply chain factors (e.g., designers, contractors, and labor); natural phenomena (e.g., weather); and client-related factors, which in KSA, have been found to include recurrent design changes by clients and poor execution of works by the lowest bidding contractor as inherent in the KSA tendering system for public sector projects and delays in approving contracts [
20]. A study conducted by Aziz and Abdel-Hakam [
21] that reviewed the factors behind delays in construction projects based on 389 questionnaire respondents in Egypt revealed up to 293 different causes, indicating the wide range of issues contributing to construction project delay. From a list of 25 potential causes of delay, a study in India found the top 5 factors included financial difficulties of contractors, the non-payment of invoices, inadequate planning and scheduling, incompetent site administration, and the high volume of client-requested changes [
22]. For healthcare projects in India, six construction delay factors were identified: a delay in progress payments, a lack of experience/ability of consultants/designers, variation and change order for scope of works, decision-making delays and litigation, inadequate coordination and communication among stakeholders, and a slow approval process by government agencies [
23]. According to Van et al. (2015), [
24], different levels of ‘integrity’ were found to be responsible for up to 19 factors contributing to government project failures and, in particular, the design phase was plagued by a lack of planning and a lack of clarity. A comparative investigation about the factors responsible for CPD in Australia and Ghana found the following causes: inexperienced contractors (43%), weak project control (21%), and the inaccuracy of potential contractors (14%) [
25]. A similar study focused on government projects [
24] identified 28 delay factors categorized into 6 groups, among which the 2 most important causes were the slowness of the client (government) in decision-making and financial difficulties by the client. A study by AlKharashi and Skitmore [
12] investigated the delay factors by measuring the impact of the delays and the degree to which each delay factor can be addressed in practice, including those associated with clients, contractors, and consultants, as well as those associated with materials, labor, contract, and those causes related to the relationship.
Another investigation from Pakistan by Hussain et al. [
26] involved a survey of 102 stakeholders and a pilot study with 16 experts in construction, from which they tested 52 delay factors as found in the literature. By comparing their results with previous studies in eight selected Asian countries, commonalities emerged, such as funding difficulties, delayed progress payment, and projects awarded to the lowest bidder. A study aimed at discovering the most significant factors that cause project delays and cost overruns investigated case studies from three countries (Australia, Ghana, and Malaysia) and found the most influential delay factors in Australia were a lack of adequate planning and scheduling, construction methods, and reliable feedback and monitoring, while for Ghana the most significant factors were a delay in payment certificates, the underestimation of project cost, and project complexity [
25]. For Malaysia, the most significant delay factors were inadequate planning by contractors, inefficient site management, and deficiencies in the experience of contractors [
25]. For Uganda, the most critical causes of construction project delays as found by Alinaitwe et al. 2013 [
27] include changes to the scope of the work, delayed payments, inadequate monitoring/control, soaring capital expenditure, and political uncertainty, whereas financial problems of the contractor were the most crucial factor in India [
22].
Additionally, various scholars [
28,
29,
30] have identified paper-based inefficient processes as being among the critical reasons behind project delays. Traditional project management practices involve tedious paper-based manual process such as data entry, recording of measurements, quantity take-offs, project monitoring, scheduling and cost control, and general contract documentation. According to Azhar et al. (2008), these kinds of manual-based approaches are prone to errors and could lead to project delays, whereas adopting building information modelling (BIM) could alleviate or eliminate some of these issues [
31]. Similar concerns were highlighted by others such as [
32], who emphasized the inefficient and error-prone ‘paper-based processes’ used in site meetings, record keeping, works inspections, and monitoring, during which project deadline pressures could result in compromised accuracy or quality, hence contributing to delays. It was also shown that for an industry that is rich in data from sources such as BIM and Internet-of-Things (IoT) sensors in its project sites, the pace of adoption of artificial intelligence (AI) and machine learning (ML) for predicting and managing delays is slow [
33]. One area where digital technology can support research into construction project delays is in understanding the synergy between delay factors. One example of a study on the interdependence of delay factors was carried out using ML algorithms for accurate prediction utilized two machine learning models (i.e., decision tree and naive Bayesian classification). The results were based on training the ML model on nine sources of delay risk, including clients, contractors, consultants, design, labor, material, project, equipment, and external factors, which produced 59 delay risk factors from data drawn from 51 construction projects in Egypt. Findings suggest that the sources of delay risk are very interdependent and complex, making time overruns challenging to manage, but using ML techniques (naive Bayesian model) provides a reliable predictive model, producing the necessary associations and allowing for better decision making that is evidence-based [
34].
Another important factor to be considered in delays to construction projects is attributed to a phenomenon referred to as ‘optimism bias’, which is a cognitive bias that leads a decision-maker to downplay the extent to which an adverse situation or event could affect them [
35]. In the construction industry, optimism bias could occur due to either the underestimation or overestimation of the expected duration or costs of a construction project [
36]. This phenomenon plays out in the form of the ‘Planning Fallacy’, where construction planners and managers exhibit optimism bias when conceptualizing and evaluating a proposed project’s duration, cost, and even benefits [
37]. From many studies in the literature [
38,
39,
40,
41,
42], it has been found that large infrastructure projects are often prone to such inaccurate time/cost estimates, and these have been attributed to optimism bias.
Other unique project characteristics that can result into delays include the type of building, where studies have found that healthcare projects are prone to delays for specific reasons. For instance, a US-based study on hospital construction found that such projects were often affected by changes much later in their execution phase due to clients changing end-user requirements and the fast-evolving nature of healthcare technologies, leading to disruptions and negatively affecting productivity, with obvious consequences for cost overruns [
43]. The sophisticated nature of hospital projects has led to the adoption of non-traditional procurement models such as the private finance initiative (PFI) in the United Kingdom, with benefits including privately managed risks in aspects such as budget/cost controls and delay management [
37,
44], as well as managing over-optimistic schedules and a poorly defined scope [
37]. For developing countries, it has been found that adopting the public private partnerships (PPP) model for hospital procurement can help stakeholders overcome some of the challenges associated with such complex projects. Some of the risk factors identified for PPP projects include the payment mechanism for the investors, as well as disputes, design flaws, material variations, cost overruns, and delays. The study concluded that a lack of effective risk allocation as well as a short-term view of healthcare investments are among the challenges that, when overcome, can improve the PPP delivery process [
45]. However, the resilience expected from PPP procurement has not always been successful, and the UK’s National Health Service (NHS) has been moving away from such models [
46].
The unique role of government as a statutory authority and as the client for construction projects is also an important to consider. In Singapore, research based on two case study hospitals showed that although project managers had prepared detailed construction programs with properly estimated activity durations and sufficient float, both projects still experienced delays due to client-based factors such as additional requirements or the changing scope of works by stakeholders, regulatory restrictions placed by the Singapore government on bringing in foreign labor, and aggregate shortage due to a foreign government’s ban on exporting aggregates [
47]. Other government-related constraints that could contribute to delays in hospital projects include statutory design compliance issues, which can manifest in designs being delayed or reworked, and, in this regard, the automation of compliance checking can speed up the design process while minimizing future reworking [
48]. The next section focuses on delays in the KSA context, where the issue of government/client-related delays will be examined further.
2.2. Delays in the KSA Construction Industry Context
The Saudi Vision 2030 identified the high quality of infrastructure as very important to meeting the needs of the country’s growing population, in addition to other critical projects necessary for the modernization and ‘Future Cities’ program [
7]. The projects necessary to achieve this vision have been subject to delays, as shown by a number of investigations conducted on the delays in KSA over the last two decades. A recent study based on 34 construction projects in KSA investigated the relationship between productivity and construction delays and found a strong association between delay factors and productivity factors (which include inefficient labor, inefficient coordination among construction stakeholders, inadequate manpower, design errors, and awarding a contract to the lowest bidder [
49]). Another study [
50] focused on Saudi Arabia reported that 662 projects valued at 40 billion Saudi Riyals were found to have suffered significant delays, which is a significant amount, with the material and technical capacity of the contractor being responsible for 82% of such delays, while regulatory obstacles were responsible for 12.2% of the delays.
Given the importance attached to key construction projects of the KSA government’s Vision 2030 ambition and the ‘Future Cities Program’ [
7], it is not helpful that many causes of delay are directly linked to the client, including poor communication, client interference, a delay in progress payment, slow decision-making by the client, changes to the scope of work, a shortage of funds from the client, and the bidding system [
50]. These factors point to culpability on the part of the client. Although other causes were found, such as poor qualifications by skilled staff, inadequate capacity by the contractor, logistics and material delivery issues, poor design management, and low productivity, among a list of 56 factors in total [
50], the prevalence of so many client-related factors is crucial to addressing delays in the Saudi context.
One study focusing on infrastructure [
51] identified three groups of stakeholders that were found to be responsible for delays in Saudi public utility projects, including consultation officers, water and sewage project owners, and sewage contractors. The study found that financial difficulties (including cash flow) were the most important factor for delays, and these could be due to reasons such as delayed payments by client to contractor, inadequate planning by the contractor, and a government policy of awarding contracts to the lowest bidder, regardless of the capacity to deliver at the accepted bid price. This study found that contractors for many medium-to-large-scale projects requested additional time. For large construction projects in the Eastern Province of Saudi Arabia, Assaf and Al-Hejji [
1] analyzed a group of stakeholders, which included 19 consultants, 15 owners, and 23 contractors, and deduced that change orders from the client were the only common cause of delay, while other main causes that were unique to each group of stakeholders included delayed progress payment and changing regulations (client), inadequate planning/scheduling (consultants and contractors) and poor and site management, a lack of necessary workforce, and construction accidents (contractors). From consultants’ perspective, a survey of 51 construction projects in the Northern Province of Saudi Arabia revealed that delays were caused by changes to design specifications, awarding contracts to lowest bidders, unrealistic project durations, frequent deviations from the original design, inflation in the cost of materials, shortages of manpower, low productivity, and delays between the completion of design and the commencement of works [
52]. A further review of the literature revealed many studies on the causes of construction delays in KSA, as summarized in
Table 1. The research methods used by these studies were often questionnaire surveys, with an analysis carried out using statistical techniques such as the frequency index, importance index, and severity index, but there were similarities in the factors identified by these studies.