Moreover, we focused on the incidents that were first reported
by individual users (79 in total). We calculated the
time difference between the first tweet shared by individual
users and the first tweet sent by users from other categories.
The results show that the individual users are reporting 24.13
minutes in average before users of other categories. This underlines
that if citizens are sharing incident related information,
they share it promptly. Nevertheless, we did not evaluate
if those tweets contain valuable situational information,
which is subject to future work. We can thus summarize
that a variety of individual users are sharing small incident
related information, though, the absolute amount of tweets
is comparably low. This is also contradicting the results of
Choudhury et al. (2012), which might be because they focus
on common events. Second, individual users are timely reporting
information. Nevertheless, large amounts of incident
related information is shared by official sources, specialized
bloggers, or journalists.