## 3 Results and Analysis
### Qualitative Comparative Analysis  
Table 6 presents the results of the Qualitative Comparative Analysis (QCA) conducted to identify causal patterns leading to cost and schedule deviations in road intersection projects across the five proposed planning and scheduling stages. The QCA utilized (1) the five planning stages proposed, (2) deficiency causes identified in the 25 analyzed projects, (3) relationships between deficiency causes and stages identified through interviews with a panel of 10 experts, and (4) classification of whether each of the 25 projects experienced cost or schedule deviations. The first column details the different stages of the planning and scheduling process. The second column displays the results of condition combinations, along with their respective consistency and coverage metrics (CG), associated with expected cost overruns. Additionally, it presents the combinations, consistency (CS), and coverage (CG) metrics corresponding to expected delays in project execution. The values highlighted in red indicate acceptable consistency and coverage levels, supporting the identified configurations' empirical and logical validity. These combinations help determine how deficiencies in schedule planning contribute to cost and schedule deviations in road intersection projects. The Qualitative Comparative Analysis (QCA) results revealed that the cause of 'Deficient estimation of material quantities' (C6) has a consistency value of 0.625 in the presence of cost overruns for Stages 2, 4, and 5 of the planning process. This indicates that in 62.5% of the projects, this cause was present when cost overruns were observed. In Stage 2, which corresponds to the 'Definition of Construction Activities', C\({}_{6}\) is identified as a critical and necessary cause for the presence of cost overruns in road intersection projects. In 81.3% of the cases, the presence of C\({}_{6}\), or its combination with C\({}_{10}\) (C\({}_{6}\) + C\({}_{10}\)) or C\({}_{16}\) (C\({}_{6}\) + C\({}_{16}\)), was necessary for cost overruns to be evident. In addition, the combination of C6 with C\({}_{13}\) (C\({}_{6}\) + C\({}_{13}\)) or C\({}_{22}\) (C\({}_{6}\) + C\({}_{22}\)) was necessary in 75.0% of the cases for cost overruns to be evident. For C\({}_{6}\), the coverage is 0.714, which indicates that 71.4% of the projects that present this cause also present cost overruns. In step 4, 'Estimating Duration of Construction', C6 presents the second highest consistency among the causes analyzed. The presence of C\({}_{6}\), or alternatively C\({}_{10}\) (C\({}_{6}\) + C\({}_{10}\)), or C\({}_{4}\), or C\({}_{7}\) (C\({}_{4}\) + C\({}_{6}\) + C\({}_{10}\) + C\({}_{7}\)), or C\({}_{2}\) (C\({}_{2}\) + C\({}_{4}\) + C\({}_{6}\) + C\({}_{10}\)) is necessary in 81.3% of the cases for cost overruns to be evident. Unlike Stage 2, in Stage 4, C\({}_{6}\) presents a delay consistency of 0.65, being the highest of the stage, which indicates that this cause is found in 65.0% of the projects that present delay. Finally, in Stage 5, 'Road Construction Schedule Development', the presence of C\({}_{6}\) or,alternatively, C\({}_{10}\) (C\({}_{6}\) + C\({}_{10}\)) is necessary in 81.3% of the cases for cost overruns to be evident, as in Stage 2. The combinations (C\({}_{6}\) + C\({}_{10}\)) and (C\({}_{6}\) + C\({}_{4}\)) with a consistency of 0.75 and 0.70, respectively, show how adding causes to a critical cause can reinforce cost overruns in road intersection projects. Thus, the underestimation of material quantities impacts direct costs and generates uncertainty and constant adjustments, affecting the project's development under compliance with the initial contractual conditions. This highlights the importance of accurate estimation of quantities of work from the initial stages, as early errors can trigger significant financial problems during the construction stage.