Where I live the government website has a database of every licensed professional in the state (which I imagine is the same in every state). You can look them up by name and profession and you'll get their license number and information related to it- when they received it, when it expires, disciplinary action, etc. If they've had complaints filed where no action was taken I don't think you'd see that but I could be wrong. Every state may vary a little but it's public information so they all will have it somewhere accessible.