M.R.
ODD is quite frequently a gateway diagnosis or a comorbid diagnosis to another developmental issue. If you have not looked into a Developmental Pediatrician for your evaluation, I would consider it as soon as possible. Psycholgist and neuropsycholgists are alternatives, and psychiatrists are terrific case managers once you have a good diagnosis, but nothing beats the thourough nature of a Developmental Pediatrician (find them at children's hospitals.) If you go into a psycholgist and ask for an ODD evaluation, that is exactly what you get. If you go to a Developmental Pediatricians office and ask for an ODD evaluation, they are going to evaluate everything else that it might be instead, and everything that it could be combined with that will need treatment for you daughter to be more functional.
ODD and sensory processing disorder sound more appealing than autism or ADHD to many parents these days, as dyslexia and CAPD did several years ago. You should let a professional evaluate, and not try to guide the diagnosis and that will be much more effective for your daughter.
My experience as an educational advocate is that if you get one of the other diagnoses, even if ODD is comorbid, you will have a better outcome and prognosis than if your daughter has stand alone ODD, which is much more difficult to remediated than ODD that has a more treatable cause.
M.