## Appendix A
### Qualitative Assessment of Buses about Perception of Credibility
From Round 1, it emerged that the source of a news article can influence its credibility; that text in news previews can be insufficient; that roughly half of the experts think that users' response on social networks can be influenced by false, bold claims; and that the most reasonable method for debunking a piece of news is to search it on other reliable sources. The round 2 questions, here reported, address the previous points with more specificity:  
* Q1 **Based on your knowledge of the domain, do you think that the source a news article is taken from is an important feature for assessing news credibility? ** Most users agreed that news outlets play a role in the perception of credibility. * Q2 **From Round 1, it emerged that information contained in news previews on social networks is often poor in terms of quality. Do you think that reading the entirety of an article can bring more useful information to decide whether the article is credible or not? ** A total of 6 out of 10 users strongly agreed, while the remaining mildly agreed. * Q3 **From the previous round, a relationship emerged between the credibility of news and users' response. Based on your knowledge of the domain, do you think that an interface that shows the opinion of the majority of users about the credibility of the news piece can be effective in influencing the opinion of an individual? ** Experts are divided, as 3 out of 10 answered \"Not much\", while 3 out of 10 answered \"Very much\". * Q4 **From the previous round, agreement about the need to check the coverage of a news piece on other sources before deciding about its credibility emerged. Whatdo you think is the percentage of users that search for the credibility of some news before making up their minds on it? **  
A total of 4 out of 10 participants indicated \"5% to 10%\", while the remaining were equally divided into \"10% to 20%\" and \"20% to 30%\". * Q5 **Considering a given percentage of users that check for the credibility of news on other sources, do you think that the majority of them belong to one (or more) of which of the following generations? **  
Overall, 60% of answers indicated \"Millennials 1981-1996\" as the generation more likely to fact-check news online, while only a minority indicated older generations, such as \"Gen X (1965-1980) \", or younger, such as \"Gen Z (1997-2012)\" (both at 20%). For almost one-third of respondents, there was no relationship between age and the propensity to search for the same news on different outlets. Round 2 answers are, to a small extent, in contrast with the quantitative findings of our analysis. The source of news was acknowledged as a very informative feature, confirming our findings (see Section 4). Respondents to the survey agreed that reading an article in its entirety could help determine its credibility; however, results reported in Section 4.2 show that this may be a misconception: users that took the Fakenewslab test performed worse, in terms of accuracy, when confronted with long texts, possibly due to the fatigue of reading excessive information. The survey panellists are divided about the effectiveness of peer pressure on individual judgement, a behaviour well-documented in literature and further confirmed by our analysis. They also underestimated the percentage of users that would search for an article on other venues, which in our test was assessed around 18%. It must be emphasised, though, that it is impossible to determine if users that left the browser's tab and came back later actually fact-checked the news; this finding must therefore be taken carefully. Lastly, users correctly indicated young adults as the most likely to carry out parallel research of the same article on other news; one-third of respondents, however, did not acknowledge any relationship between age and propensity to fact check.