## 4 Results and Discussion
### Cross Analysis: RQ3 vs. RQ2  
We have analyzed the reported impacts (RQ3) and related them to the RE activities (RQ2) in which they occurred. Table 12 shows the support level (primary papers) identified for these relationships. Table 12 depicts the plotting of papers with RE activities whereas Figure 4 shows the overall trend of RE activities in respective papers.  
Figure 4 visualizes the distribution of references on each category of impact (RQ3) along the RE activities (RQ2). The activity with the highest support level is Elicitation (in blue color, next to the  
\begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline
**RQ3/RQ2** & **Elicitation** & **Specification** & **Analysis** & **Validation** & **Change Mgmt.** & **Other** \\ \hline Guidance and understanding & S32, S34, S59, S61, S27, & & S06, S20(4), & & & & \\ S62, S66, S68, & & S23, S45, S64, & S40, S42, S81 & S46 & S50, S57 & S53(2), S89(2) \\  & S70, S86 & S65, S75, S76(2) & & & & & \\ \hline Automation and tool support & S12, S28, S55, & S04, S33, & S11, S43, & & & & \\ \hline Identification of conflicts and defects & S39, S84, S86 & S18, S26, S36 & S02, S43, & S07, S11, & S00 & S24 \\ \hline Completeness, correctness and accuracy & S28, S59, S69, S82, & S14, S17, S78 & S38 & S74 & & & \\ \hline Quality & S73, S86 & S26, S78, & & & & & \\ \hline Reusability & & S04, S22, S30 & & & & & \\ \hline Ambiguity & S70 & S18, S41, S58 & & S10 & S71 & S09 \\ \hline Elicitation & S02, S13, S62, S68, & S25 & & & & & \\ \hline Testing and traceability & S28 & S63 & S40, S49 & S21(2) & S57 & & \\ \hline Productivity and time reduction & S70 & & S60 & S07, S79 & & S37, S80 \\ \hline Communication & S87 & S65 & S31 & & S03 & S87 \\ \hline Consistency & S29 & S48 & S38 & S54 & & & \\ \hline Evolution and maintainability & S40 & & & & S01(2) & S15 \\ \hline Costs & & & S51 & S72 & S37 \\ \hline Validation & S27, S12 & & & S74 & & \\ \hline Control and coordination & & & & & S03(2) & \\ \hline Modelling & & S77 & & & & \\ \hline \hline \end{tabular}
\end{table}
Table 12: Categories of impacts in every RE activity.  
Figure 4: RQ3 vs. RQ2.  
horizontal axis) with 44 primary papers, in almost every category, except for Reusability, Costs, Control and Coordination, and Modelling. We think that the absence of impacts on these categories during the Elicitation is due to the early nature of the activity (first steps of RE). The vast majority of the support level is concentrated on Guidance and Understanding, by providing the developers with structured knowledge guides (ontologies and taxonomies) to conduct the elicitation process and facilitating the understanding of the collected requirements between all the stakeholders.  
All the impacts of CVs affected the Specification activity, except Productivity and Time Reduction, Evolution and Maintainability, Costs, Validation, Control and Coordination and Modelling. Note that just because little or no support has been identified for a given RE activity, does not mean it does not exist. It is frequent that researchers report only those aspects that are more attractive or interesting, leaving aside the more trivial ones (least important).  
Analysis is the third most mentioned RE activity, but far from the previous two. The reason for this decrease can be found in the work of disambiguation and specification that have been carried out in the first two activities. During the analysis of the requirements, they have been already refined enough to make the current use of the CVs not so critical. Figure 4 shows the details of this cross-analysis of the two variables, the Impacts and the RE activities where they happen.