It's quite hard to gather anything of importance. You have to remember that some of the best candidates work full time on their company's private repos. If they

It's quite hard to gather anything of importance. You have to remember that some of the best candidates work full time on their company's private repos. If they do have their own projects, they might be using a diff VCS. Either way, there are too many variables to make a github have any warning signs, but it's a good data source along with everything else to get a better idea of a candidates background.