# How Dramatic Events Can Affect Emotionality in Social Posting: The Impact of COVID-19 on Reddit
## 4 Data Collection  
In this section we describe the data collection phase we conducted for this work, and we present the datasets we considered for the analyses. All collected data are available for download at [[https://bitbucket.org/cauteruccio/reddit-dataset](https://bitbucket.org/cauteruccio/reddit-dataset)]([https://bitbucket.org/cauteruccio/reddit-dataset](https://bitbucket.org/cauteruccio/reddit-dataset)). Since in this study we focused on the effect of COVID-19 on social posting, the adopted dataset should provide all of the content produced during the time span of the corresponding epidemic. This dataset should be homogeneous, in the sense that all of the content should directly refer to the COVID-19 epidemic. Moreover, the dataset should take into account the diversity in space and time: people in a country mildly affected by the epidemic might show a different behavior in social posting with respect to people in a severely affected country. As pointed out in the Introduction, in order to cope with these requirements, we focused on Reddit megathreads since they refer to particular contexts or situations, and they can be country-specific. Moreover, it is worth noting that subreddits are moderated; this ensures that only pertinent comments are included in the discussion. In order to build the dataset, we started by searching for country-related subreddits following the wiki page of /r/ListOfSubreddits; this page provides a summary of several subreddits categorized from different points of view, including geography. Then, for each country-related subreddit, we manually identified each subreddit containing COVID-19 related megathreads, and we considered the time span starting from 1 January and ending to 30 June 2020. We focused on the following subreddits, namely /r/italy, /r/de, /r/thenetherlands, /r/sweden, /r/unitedkingdom and /r/nyc. In particular, our choice was based on the fact that all of these subreddits present daily or weekly COVID-19 related megathreads. Note how each subreddit represents a country, except for /r/nyc; as pointed out in the Introduction, with a little abuse of terminology we refer to data from New York City as data from a country. It is important to point out that, to the best of our knowledge, a COVID-19 megathread initiative regarding the United States in its completeness is not present on Reddit; thus, we only considered the /r/nyc subreddit due to the presence of the megathreads in it and due to the fact that New York City was one of the first places in the United States to experience the COVID-19 epidemic; as a consequence, it provides more data in the considered time span. For each of these selected subreddits, we retrieved all of the COVID-19 related megathreads. Megathreads are simply recognized by the title; in fact, each COVID-19 related megathread within a subreddit always reports the same title, in which only the date changes (as an example, the title \"Megathread Coronavirus * 16/05/20\" represents a COVID-19 related megathread in the /r/italy subreddit). Then, for each of them we retrieved all of the available comments, and we discarded all the comments marked as deleted. For each megathread, we stored the author, i.e., the user who posted it, the title, the posting date and time, the score and the number of comments. For each comment, we stored the author, the content of the comment, the posting date and time, the reference to the parent entity and the score. We retrieved all the data using pushshift.io service ([37]). Table 2 reports a summary of the main statistics for each considered subreddit. /r/italy and /r/thenetherlands contain the highest and the lowest number of megathreads, respectively. Considering the early outbreak of COVID-19 cases in Italy, this number is somewhat expected. The lowest number of megathreads in /r/thenetherlands is explained by the fact that they are weekly; this means that each new megathread is created at the start of the week.