## 4 Results
### Evaluation of Platform Characteristics: Non-Functional Requirements  
Regarding non-functional characteristics, the most important aspect to consider is whether or not the platforms are accessible to users with disabilities. To fully understand accessibility standards available in current tourism platforms, two online automatic tools--_AccessMonitor_ and _\"Test de Accesibilidad Web\"_ (TAW)--were used to examine the 10 websites, which host the before mentioned tourism web applications. The two tools were used to take into consideration WCAG 2.0 guidelines and the A, AA and AAA conformance levels. _AccessMonitor_ indicates a global index, which is a quantitative scale (ranging from 1--very poor web accessibility practices to 10--excellent web accessibility practices), and errors found by the degree of compliance (A, AA and AAA). On the other hand, TAW presents the results divided into three categories: (i) \"problems\" (corrections required); (ii) \"warnings\" (review is required); and (iii) \"not reviewed\" (manual review is necessary). In both tools, the only input needed is the URL of the tourism platforms. The results presented in Table 4 were obtained with _AccessMonitor_. The global index varies between 4.5 and 8.6, with half of the websites being classified as having regular accessibility practices (index between 4 and 5). However, there are two websites with very good accessibility practices (index between 8 and 9). Errors of type A are the most critical but also the most common, ranging from a minimum of six to a maximum of 16 detected errors. This indicates that every site has at least one type A error. Regarding the AA and AAA levels, some minor errors were also found, which influences the totality of errors. Comparatively, the platforms _Jaccede_ is the one with fewer reporting errors and _Tur4 All Portugal_ is the one which obtained the best global index score. On the other hand, the _Getaboutable_ is the platform with the most detected errors, and _Tourism for All_ is the one that registered the lowest global index score. Table 5 illustrates the results obtained with the _TAW_. The outcomes of this evaluation summarize the number of problems detected, categorized within the four principles (perceivable, operable, understandable, and robust) and the 12 guidelines of the _WCAG 2.0_. All platforms seem to have more problems of the perceivable type, especially guideline '1.1 Text Alternatives'. Additionally, the robust and operable principles also displayed a substantial number of problems in all tourism platforms. In contrast, the lowest number of problems was registered in the understandable principle. \begin{table}
\begin{tabular}{l c c c c c c c c c c} \hline \hline \multirow{2}{*}{
\begin{tabular}{} \end{tabular} } & \multicolumn{10}{c}{**Platforms**} \\ \cline{2-11}  & **Tourism** & **Hands to** & **Dissover** & **ENAT** & **Tur4 all** & **PREDIF** & **Reisen** & **Jaccede** & **Euans** & **Autism** & **Cetaboutable** \\ \hline Global Index & 4.5 & 8.2 & 6.9 & 8.6 & 5.7 & 6.4 & 4.6 & 7.8 & 5.7 & 5.0 \\ Errors type A & 11 & 10 & 11 & 12 & 15 & 14 & 6 & 11 & 14 & 16 \\ Errors type AA & 2 & 2 & 3 & 0 & 4 & 3 & 2 & 3 & 6 & 7 \\ Errors type AAA & 1 & 2 & 2 & 1 & 3 & 2 & 0 & 2 & 3 & 3 \\ Total errors (A + AA + AAA) & 14 & 14 & 16 & 13 & 22 & 19 & 8 & 16 & 23 & 26 \\ \hline \hline \end{tabular} Source: Own elaboration.  
\end{table} 
Table 4: Global index scores and errors in web accessibility of accessible tourism platforms. It should be pointed out that there are guidelines with no detected errors. These guidelines are 1.2 Time-based media; 1.4 Distinguisable; 2.1 Keyboard accessible; 2.2 Enough time; 2.3 Seizures; and 3.1 Readable. This means that platforms tend to provide alternatives to time-based media, content is distinguishable, all functionalities are available from a keyboard, enough time is provided to read and use content, the content does not cause seizures and the majority of content tends to be readable. The best results were again obtained by _Tur4 All Portugal_.