Thoughts:
So far it appears there is no law about who can diagnose. What there is is:
- description of a rubric to grade a expert witness
- general description that states cannot operate outside area if training and competence (but how to define that area is absent)
- core services / FFPSA law mandating evidence based, trauma Informed, Clearinghouse designated, best available science, meet particular needs of family
- law (or in draft) defining trauma Informed
- licensing and professional associations standards and code of ethics regarding non black and white values and efforts mandates
- there are laws that say if you can call yourself a doctor, therapist, etc, but non if them limit what they can or cannot do
- therefore, legally, anyone can diagnose anyone with anything, including DSM codes, and you can take money for it...you just can't call yourself any of the protected titles
So, when it comes to who is "legally qualified" or a "legally allowed expert", (which is just the expert, and not ultimately the credibility of the "evaluation/recommendation" it comes down to just who can provide a stronger argument that the expert in question is "more expert" than the other "expert". It's the exact same concept as scientific theory. You can't "prove" a scientific theory. You can only provide increasingly stronger (ultimately just means, whether for good reasons or bad, the emotion that something feels stronger or better) arguments that it is true. As in you can't prove "expertise" or that an eval is correct. However, you can "disprove" expertise or scientific theory.
In psychotherapy there is an enormous gap of a system that gives a credible prediction of what a "provider" is likely to soundly be able to evaluate (and further a system for them to soundly know when and how to refer out). Perhaps some kind of "certifications needed" section for each DSM code.
So what you can do is:
- used the defined law and prof orgs law and ethics as rubrics (like a grading table), the table in this paper is a good one to incorporate, to make an argument of strongest expert.
- you can also get more than one expert or experts from different areas which have all of them agreeing
- strategy: also send evaluation off to credible authority to get their endorsement
- strategy: do that memorandum thing (ABA guide how to influence judges) to advance submit law and argument to judge
- all of this is the exact same issue, concept, and strategy to battle "reasonable efforts"