<p>I think doing well at a Penn summer program helps you stand out a little, but it will not guarantee that you will get in. I did a summer program at Penn before my senior year and I know of quite a few kids from the program who now attend Penn. Whebn I took a class at Penn, another kid from the class received most likely the same grade I did and we both got letters of recommendation. However, they got deferred and ultimately did not get in while I was accepted ED so obviously there were other factors that came into play.</p>