The first quote you pulled requires the preceding sentence for context.

Despite these assumptions, from 2000 to 2006 organized civilian populations successfully employed nonviolent methods including boycotts, strikes, protests, and organized noncooperation to challenge entrenched power and exact political concessions in Serbia (2000), Madagascar (2002), Georgia (2003) and Ukraine (2004–05), Lebanon (2005), and Nepal (2006). The success of these nonviolent campaigns—especially in light of the enduring violent insurgencies occurring in some of the same countries—begs systematic investigation.

The second quote you pulled merely precedes an explanation of how the authors attempted to address the difficulty of separating violent campaigns from nonviolent campaigns.

In many cases, both nonviolent and violent campaigns exist simultaneously among different competing groups… To address these difficulties, we established some standards of inclusion for each of these categories. The list of nonviolent campaigns was initially gathered from an extensive review of the literature on nonviolent conflict and social movements. Then we corroborated these data using multiple sources, including encyclopedias, case studies, and a comprehensive bibliography on nonviolent civil resistance by April Carter, Howard Clark, and Michael Randle. Finally, the cases were circulated among experts in nonviolent conflict who were asked to assess whether the cases were appropriately characterized as major nonviolent conflicts, and also which notable conflicts had been omitted. Where the experts suggested additional cases, the same corroboration method was used. The resultant data set includes major resistance campaigns that are primarily or entirely nonviolent.

In an examination of 323 violent and nonviolent resistance campaigns, between 1900 and 2006, nonviolent campaigns achieve partial or full success at twice the rate of violent campaigns

https://www.researchgate.net/publication/240678278_Why_Civil_Resistance_Works_The_Strategic_Logic_of_Nonviolent_Conflict