You can search for certified FileMaker developers on the FMI website.
Since the introduction of FileMaker Certification with the introduction of version 7, Goya staff have been among the first developers to be certified with each release. We have developers who are certified at every level from 7 through to 11 available to work on your projects.
FileMaker Inc doesn't have a great description available of why you should hire someone who is certified as opposed to someone who isn't. But the gist of it is that it gives you some indication that we know what we're talking about. We're not going to sell you a lemon, and we're going to be around for a long time to come.