I believe that probably the study being referred to (although there may be others as well) is
Rosatte, R.C. and MacInnes, C., 1989. Relocation of city raccoons. Ninth Great Plains Wildlife Damage Control Workshop Proceedings: USDA Forest Service General Technical Report: Great Plains Agricultural Council, 87-92.
I have not read it myself. It is cited in quite a lot of places as having consisted of relocating (dunno the number of) radiotagged raccoons from Toronto to areas to the north (probably around where I am, in fact), and they say that 60% of the relocated individuals were dead within, IIRC, six months.
An additional concern is that relocation of trapped animals contributes to the speed with which disease spreads. This includes, though is not limited to, rabies.
Also it is usually fairly pointless from the property owner's point of view. There are a roughly infinite number of raccoons or most other common predators out there. Removing (or killing, either) the ones that visit your property just means that others will move in tomorrow or next week. The only point I can see in getting rid of a predator is if a *particular* predator has become unusually intent on breaching your defenses. In that case you may get some benefit. Otherwise you are just on a treadmill of perpetual removal.
If you are *going* to try to get rid of predators, though, personally I think that a bullet through the head is much much more humane than releasing them to mess up *other* animals' lives and most likely die an unpleasant fast-or-slow death in an unfamiliar place with hostile neighbors.
Seems to me prevention is better, even if the cost requires extra scrounging or cancelling cable or forgoing soda pop and pizzas for a few months or whatever. It really IS possible to build pretty much predator-proof coops and runs (well, if you have seriously chicken-loving bears, it may not be economically feasible, but I mean, other than that).
JMO,
Pat