Depends .... A lot of bikes are stolen for joy rides or to fund a minor drug habit ... those folks will steal what is easy. Best deterrent there, is a big fat lock and chain---if the bike is Visibly locked, by someone who obviously knows how to lock a bike. When I lock up at the hardware store or gym, I use two locks---anyone who wanted to could disable either lock in five or fifteen minutes, but most sneak-thieves don't want to spend that much time or energy.
If you have a bike actually worth stealing and selling, then you need a Fahgedaboutit-sized lock---which weighs more than the lightweight, expensive bike. What's the point? And no matter what you use for a lock and chain, a grinder can grind through it. The pros who go out and load a van full of high-end bikes a couple times a weekend, know what bikes are worth stealing and have the tools to defeat almost any lock quickly. Clarification": any lock or chain can be defeated, but the pros are not going to spend five or fifteen minutes and two batteries grinding through a 70-pound chain (most will cut through whatever the bike is locked to.)
On a college campus, Anything will get stolen. $50 Craigslist bikes, free bikes picked up of the side of the road .... anything. Your hope is that there is a better bike on the rack that is easier to steal.