**2. Schedule Delays—An Overview from Literature to Legislation**

## *2.1. Time Overrun in the Scientific Literature*

Time overruns are generally represented as being a consequence of the more important project management issue, cost overrun, which has been amply investigated in the literature on public and private works. So, cost and time overruns are seen as related in most theoretical works (see, for instance, References [1,2,7]) and empirical research (see, among others, References [5,8–11]), though some studies, mostly developed in emerging countries, have addressed cost and time overruns as two separate issues [12–15].

Studies on underperformance in public works can be divided into three main groups. One comprises research conducted by modeling samples of project data to predict increases in the costs and time required to complete them [16–20]. Among others, the methods most often used in such studies are—fuzzy logic "to model the relationships between the characteristics of a project and the potential risk events that may occur" ([18], p. 503); econometric analyses, such as the multistep approach [21–23], the three stages square technique [24] or the stochastic Global Cost [25], which can be used to estimate the effects of factors associated with the contract bidding process, the type of project and the design; and artificial neural networks [26,27]. This kind of research is not extensively discussed here because it is beyond the scope of the present work but it is worth mentioning that the most common "root causes" of rising costs and delays are the size of the project and an underestimation, in the project design and development phase, of risks relating to conditions on-site [28,29]. The second group of studies examines the main causes of cost and time overruns mostly taking a qualitative approach, such as structured and semi-structured interviews with the actors involved in construction industries [12,15,30]. This type of analysis probably accounts for the bulk of the international literature and it mainly generates a taxonomy of causes, divided into categories ranging from project design to the structure of public contracts. The third group of studies includes statistical analyses and efforts to design a theoretical framework for cost and time overruns [31–33]. A general consensus identifies the underestimation of risks and uncertainties as the core reason for rising costs and delays, especially in major and mega-projects. Flyvbjerg defines public authorities' and developers' tendency to underestimate potential problems as an "optimism bias" [27] that prevails over any "strategic misinterpretation" [2] in explaining why the costs of a project are underestimated and its benefits are overestimated. Flyvbjerg's theoretical explanation is disputed by Love [34], who shifts the focus to distortions in competitive tendering to select project design firms and building contractors—the selection process tends to compress the fee excessively and to raise unrealistic expectations regarding design aspects and the paperwork involved. van Marrewijk et al. [33] also consider the restrictions imposed by project governance as interfering with the proper management of a project's development. This focus on the role of laws and norms in project management moves away from the majority of the literature on the topic of cost and time overruns, which tends to underscore the centrality of the design and planning phase of the process.

Far fewer research articles have concentrated on time overruns, in particular and on the role of procurement in causing them. After conducting a questionnaire-based survey, Larsen et al. [10] support the conviction that delays are largely due to poor project design and planning but they also highlight the different incidence of these factors on the time to completion, cost and quality of a project. Sepasgozar et al. [35] conduct a systematic bibliographic review on time delay in construction projects and highlight the potential of the new digital tools such as BIM to reduce the delays. Assaf and Al-Hejji [30] analyze major project delays in emerging economies. A survey conducted on owners, consultants and contractors identified several factors affecting time constraints—all three parties agreed that the most important causes of time overruns were changes in government regulations and laws, job site management issues and accidents during the construction phase. They also mentioned the relevance of workforce quality and productivity. These are issues more likely to affect building works in emerging economies than in Western countries (where the literature has focused on shortcomings in planning and an underestimation of the risks in the design phase). Nevertheless, studies conducted in the Far East have also pointed to the role of contractual commitments and the need to avoid litigations between owners and contractors as crucial factors influencing the expected time to complete a development [36].

As for the Italian context, Guccio et al. [37] identify the dimension of the public government body involved as a key factor in time overruns. They report empirical research leading to the conclusion

that projects promoted by local authorities took longer to complete than works commissioned by the country's central government. Along the same lines, when Gori et al. [4] analyzed a dataset concerning public works in Tuscany (central Italy) for local authorities, they found that "insufficient procurement experience is associated with a higher probability of incurring delays and longer work durations" (p. 822). Public works require a level of specialization that not all local authorities possess [38].

The present empirical analysis contributes to the literature on these issues, focusing on small and medium-sized projects and highlighting the role of national regulations on public works as a potential cause of delays.

### *2.2. Italian Legislation on Public Works*

The so-called Code of Public Works, Services and Supply Contracts (Legislative Decree n. 50/2016) is the latest in a number of revisions of the regulations covering the awarding of public works to have been implemented in Italy over the last 50 years. The revisions were needed partly to comply with EU laws aiming to improve the "design" of contract awarding procedures and to enforce "principles of publicity, transparency and equal treatment" ([32], p. 210). Since 1999, the first year covered by our analysis, the legislation on this matter has changed significantly at least three times.

The Code essentially considers three main aspects—the phase of the works to be awarded (i.e., design, construction, and/or works management); the procedure for selecting the contractor; and the selection criteria. The Italian regulations envisage two types of agreement—the procurement contract; and the concession contract. The former relates to the construction phase or, rarely, to the executive project design and the construction. The latter covers construction and works management. The competition procedures covered by the Code are the most important aspects of the process for our purposes here because they can play a remarkable part in explaining delays in the completion of the works. There are four types of tender:


The first, open procedure is one of the most often used. There is a call for tenders containing a detailed description of the object of the contract and the characteristics required of potential bidders. Fulfillment of all the requirements is only ascertained when the bids are examined. The restricted procedure is used for works costing less than €1.5 million. It involves an initial prequalification phase to ascertain what requisites a contractor will need and then identify at least five enterprises to invite on the basis of their expertise and technical endowment. Then only selected enterprises are invited to a second bidding phase. In the third type of procedure, invited enterprises make a bid on the grounds of which negotiation is conducted to improve the proposal both technically and economically.

As Decarolis and Giorgiantonio explained [39], in Italy there is not much difference between open and restricted procedures because all applicants fulfilling the requirements must be invited to make a bid when the value of the work is less than €40 million.

The last procedure applies to a very limited number of cases, mostly in emergencies or in cases where only one enterprise is capable of doing the work. The public administration asks the enterprise in question to make a bid for the work and then negotiates with them to improve on their proposal.

In the case of public-private partnerships (PPP), for project financing, for instance, the awarding of the contract is divided into two phases and the second phase involves a restricted procedure with negotiation.

There are basically two criteria for assigning the works—the "lowest price" and the "economically most advantageous offer." Clearly, the former only considers the lowest price of the works. The latter takes into account a set of other aspects of the bids as well as the price, such as the quality of the urban and project design, the duration of the building works, energy cost savings and lower maintenance

costs. The selection is based on a scoring rule. In both cases, administrations must check for abnormal tenders or abnormally low offers. Checking for excessively low offers is a long and complicated process that varies depending on the type of bidding procedure used. The contracting authority has to set a threshold for the abnormal offer and ask the bidder for clarification. The bidder can dispute the authority's observations. Abnormal offers must be examined for works costing more than €1 million, while for works costing less abnormal offers may be excluded automatically. This screening of bids may give rise to delays that are impossible to account for in the design or construction phases but the building work may be postponed depending on the duration of the contractor selection process.

It is worth mentioning that, for PPPs, the documentation needed to present a bid includes a demonstration of the value for money (VfM) of the proposed works. We do not discuss the question of VfM here because it is beyond the scope of the present contribution.
