Personally, I prefer a compendium like this that only gives a reference to the source material for each instance, which lets me confirm the credibility of each event for myself. A few years ago the media and gun control advocates all over the internet were constantly using this website "shootingtracker" as the authority on how many mass shootings were taking place. But if you actually bothered to check that site, it had its own independent (lower standard) definition of what constituted a 'mass shooting,' they de-emphasized access to sources, and they were including events as 'mass shootings' that involved toy guns, bb guns, and counted people who sprained their ankle as shooting victims. Many of their sources were just dead links. It was geeks at Reddit, ironically, who audited the site to pieces and showed how full of shit it was. As a result, Shootingtracker changed its definition to the standard one used by the FBI, but I never see anyone, in particular the media, using it as "the authority" anymore, and for good reason.