# Cost Overrun Causative Factors in Road Infrastructure Projects: A Frequency and Importance Analysis
## 3 Results and Discussion
### Qualitative Analysis  
#### 3.3.1 Qualitative Analysis by Factor  
From the ten most important cost overrun factors reported in each of the 18 documents, 38 were identified and classified into 14 categories. In the same way, five stakeholders' groups, responsible for the cost overrun phenomenon occurrence, were identified and assigned to the factors: (1) contractor, (2) designer and consultant, (3) external agent, (4) owner, and (5) supplier and subcontractor (Table 4). The 'failures in design' factor is the one with the highest frequency (Table 4). During the construction phase, several inconveniences occur due to design failures such as errors, inconsistencies, and incomplete information [77]. When a design failure occurs, the contractor must consult the designer team and wait for an answer. Therefore, the design changes could affect the continuity of on-site activities and generate additional costs. This problem can be aggravated when a long time elapses from the design completion until the beginning of the construction phase since an updating of the design norms can occur and other unexpected events. Thus, design issues can affect the continuity and characteristics of construction processes, which can lead to the cost overruns occurrence. The 'price variation of materials' factor is the second most frequently reported factor, which is usually caused by economic phenomena of external nature to the project. This factor is usually beyond the control of the internal stakeholders of the project because the phenomena are related to aspects such as the law of supply and demand, economic volatility, variations in exchange rates, inflation, and others, which can affect the price of materials, producing an increase with respect to the initially estimated costs. The 'inadequate project planning' factor is the third most frequently reported. This factor is associated to planning processes deficiencies that are usually related to: poor work scheduling, planning deficiencies for materials supply, absence of plans for machinery acquisition, lack of goals and deliverables projections, planning of hiring personnel, lack of plans for traffic management, scarcities in environmental issues planning, among others. Deficiencies that cause improvisation at the construction stage, causing costs not considered in the initial estimations. With the same frequency of the 'inadequate project planning' factor, the 'project scope changes' factor is the third most frequently reported, which is related to the works that are added to those established in the initial contract. Such additions usually occur during the construction development and can be caused by issues associated with unforeseen and complementary works, terrain conditions, relocation of underground utilities, environmental issues, owner's requirements, and others. Unforeseen issues that turn into additional costs that cause the cost overruns phenomenon. The 'design changes' factor is the fifth most frequently reported. Design changes can greatly affect the costs associated with the project, considering that design modifications can be made at different times of the project lifecycle, generating waiting unplanned times for the design resolution. Times that could lead to delays in activities, rework, labor occupation instability, additional payments by machinery and wages, additional works not quantified in the budget, contract extensions, charges by consultants, and designers, among others. With the same frequency of the 'design changes' factor, the 'unrealistic contract duration' factor is the fifth most frequently reported. Excessive optimism in estimating the contract duration may lead to the contractor being unable to carry out the activities on the schedules planned for the construction stage. Thus, the schedule lags can propitiate the delay phenomenon occurrence, as a consequence, the contractor must make additional unforeseen payments related to wages, machinery, facilities, among others; scenarios where additional payments can become cost overruns.