Vital signs are done by the nurse or medical assistant.
Very important that the results are correct because the doctor makes his decision of the patient treatment and diagnosis from the vital signs.
You should be alert to any significant changes and report them to the doctor and in documenting them because they may indicate a change in the patient's condition.
When incorrect results are given the patient suffers because the doctor has treated the patient with wrong decision.
If the doctor feels you aren't getting correct results and he has to check behind your work then he will also feel he doesn't need you.
So--be sure you know how to do vital signs correct if you plan on keeping your job.