Could you describe the benefits of using a functional measures such as the National Outcomes Measurement System (https://www.asha.org/noms/) while developing a POC and determining patient progress in therapy?

Please you have to answer the following 3 questions.
1. How are functional evaluations different from classic formal aphasia tests?
2. Could you describe the benefits of using a functional measures such as the National Outcomes Measurement System (https://www.asha.org/noms/) while developing a POC and determining patient progress in therapy?
3. How could informal measures or criterion based evaluation affect the ability of the clinician to generate a differential diagnosis?