In the UK a number of dog training associations which share a common system of values and standards of professional conduct have become signatories to a Dog Training and Behaviour Charter. You can read about it here: https://ukdogcharter.org/ Anyone looking for a dog trainer or behaviourist can know that if they contact someone belonging to the organisations listed that they are guaranteed a certain standard of conduct and advice from the trainer and that the trainer has been assessed and takes part in continuing professional development.