This is an innovative Randomized Controlled Trial.
Hofmann J, Zotter H, Kerbl R: How to dress as a paediatrician? Acta Paediatrica 2012, 101(12):1260-1264.
“One hundred and seven children and 72 parents were visited by a paediatrician randomly wearing one of the three different outfits (casual, semiformal, formal) during a hospital stay.” They were then asked what they thought.
Parents and children preferred the casual style, and parents trusted the doctor just as much regardless of dress.
This is the figure from the article showing the different styles.
Yay! Its T-shirt time. Now I know why I never wear a tie.
Neonatal Research 
glad you are not wearing a tie! evidence shows that ties are not changed often in male physicians and are carriers of infection…glad to see this article.