## 3 Results and Analysis
### Qualitative Comparative Analysis
C6 when combined with other causes such as: 'Omission or deficiency in the definition of work packages (WBS)' (C\({}_{13}\)), 'Lack of experience of the planner' (C\({}_{10}\)), 'Omission of road markings in planning' (C\({}_{16}\)), and 'High complexity of construction work' (C\({}_{22}\)), can increase the presence of undesired scenarios at different stages and potential cost overruns in projects. Lack of experience can lead to inaccurate estimates of materials, time, and resources needed, while C13 and C16 result in incomplete and disorganized planning, requiring continuous adjustments and causing workflow disruptions. In addition, C\({}_{22}\) adds an additional difficulty level, increasing the likelihood of errors and the need for revisions and corrections. Consistency of the cause 'Lack of experience of the planner' (C10) for cost overrun and delay is 0.750 and 0.650, respectively. This indicates that this cause is present in 75.0% of the projects with cost overruns and 65.0% of the projects with delays. The presence of C\({}_{10}\), or alternatively its combination with C13 (C\({}_{10}\) + C\({}_{13}\)), is necessary in 75% of the cases for cost overruns to be evident. In comparison, its combination with C\({}_{16}\) (C\({}_{10}\) + C\({}_{16}\)) is necessary in 93.8% of the cases and with C\({}_{22}\) (C\({}_{10}\) + C\({}_{22}\)) in 81.3% of the cases. In addition, the coverage of the combinations of C\({}_{10}\) with C\({}_{4}\) (C\({}_{10}\) + C\({}_{4}\)) or C\({}_{4}\) with C\({}_{6}\) (C\({}_{4}\) + C\({}_{6}\) + C\({}_{10}\)) indicates that 70.0% and 80.0% of the projects that present the cause also present delay. 'Omission or deficiency in the definition of work packages (WBS)' (C\({}_{13}\)) is mainly identified in the stage 'Definition of Construction Activities', with a consistency of 0.625, indicating that this cause is found in 62.5% of the projects that present cost overruns. The combination of C\({}_{13}\) with C\({}_{22}\) (C\({}_{22}\) + C\({}_{13}\)) has a consistency of 0.813, indicating that it is necessary in 81.3% of the cases for cost overruns to become evident. Individually, C\({}_{13}\) is less necessary for delays to be evidenced with a consistency of 0.20. Combinations of causes in addition to the planner's lack of experience, such as 'Omission or deficiency in the definition of work packages (WBS)' (C\({}_{13}\)), 'Omission of road markings in planning' (C\({}_{16}\)), 'High complexity of construction work' (C\({}_{22}\)), and 'Inadequate estimation of permit acquisition durations' (C\({}_{4}\)) provide critical determinant scenarios in the appearance of cost overruns and delays in road projects. An inadequate WBS aggravates the lack of experience due to the impact on costs and time generated by omissions of critical activities. These omissions may be reflected in cause C\({}_{16}\) since the omission of road markings may require adjustments during the construction process that could affect the development of the schedule. The cause of deficiency, 'Omission of road markings in planning' (C\({}_{16}\)), is mainly present in the stages of the 'Road Schedule Management Planning' and 'Definition of Construction Activities'. The proportion of projects with both a C\({}_{16}\) cause of deficiency and the presence of cost overrun among the total number of projects with cost overrun is represented by 56.3% and for delay by 60.0%. Combinations of C\({}_{16}\) with C\({}_{3}\) (C\({}_{3}\) + C\({}_{16}\)) or C\({}_{22}\) (C\({}_{16}\) + C\({}_{22}\)) increase the consistency to 75.0% and 81.3%, respectively, for cost overruns with a coverage of 66.7% and 65.0%, respectively. For delay, the consistency and coverage of these combinations do not vary significantly, being the most representative cause of deficiency in Stage 1.