After working with several students, it is clear that confidence is nearly as important as competence. In the example above, you may not have the entire answer, but the demeanor in which you present yourself completely changes the context of the answer. In several situations, a student has answered a patient's question, and the patient turns to me to get a second opinion. Almost always, the students answer is correct. The patient wants a second opinion because he knows the student was hesitant in his/her response.
Ideally, confidence and competence would grow together- the more you learn, the more confident you become. Realistically, it takes multiple repetitions in the clinic to become confident in your interactions with patients. Building trust in the patient can be a difficult task. You must be honest with your patients, but your demeanor can greatly change the outcome of the patient interaction. The video below is not physical therapy related, but it sends a good message regarding body language.
How do you carry yourself? What is your body language in the clinic? How is your body language affecting your patient interactions?