Author here. I plan to add a "how it works" section, but the basic idea is that each news story is rated on several parameters:

- scale is the number of people affected by the event described in the news story. - magnitude is the strength of the effect. - potential is the likeliness of the event to lead to other, more significant events. - source credibility considers how trustworthy is the source, and what is its track record.

Then these parameters are combined into a single score.

Also fair criticism re: repeats. I plan to solve this by clustering similar news, so one event is only given one title.