In more complex cases, diagnosis is as much art as science. There aren't always evidence-based clinical practice guidelines to follow so clinicians often have to rely on experience and intuition. Subjective judgement is a factor.

Under HIPAA, patients do have the legal right to correct errors in their medical records.

https://www.hhs.gov/hipaa/for-individuals/medical-records/in...

they do, culturally. However, data does influence their decisions. Appropriately diagnosis are probability based and is an art. Its not perfect, but currently it is good