Fig. 3: Number of users, number of users who posted at least one crime-related tweet and concentration of tweets among users (divided by all tweets, crime-related and violence-related tweets) measured using the Gini coefficient of the number of tweets.

The Gini coefficient is a metric frequently used to measure income inequality and it is obtained by comparing the observed distribution of wealth against the hypothetical case in which all individuals have the same wealth. Here, the Gini coefficient is computed by comparing the number of tweets per account against the case in which all accounts publish the same number of tweets. The lowest Gini coefficient means that more users engage with crime issues in their country.