The problem with photography is that you can't create an organisation to regulate the quality of work. For example I for one happen to think that almost all contemporary art photography is not my cup of tea. And while I can generally appreciate good photography in fields that I don't specialise in, appreciating contemporary photography is beyond me, in the same way that appreciating something like Piet Mondrian or Jackson Pollock is beyond me.
So who decides? Ultimately the client is the boss, and it doesn't matter if my photography is rubbish; if a client likes my work, it's good work.