Sweepstakes, Contests or instant winner games

There are so many variables to take into account when comparing different sweepstakes that valid industry benchmarks remain elususive.
I've yet to come accross any reliable predictors and would caution you not to put too much stock in any that you use. The important thing to keep in mind when planning a sweepstakes is that they are objectives driven promotions and it's important to be sure to choose the sweepstakes tactic that matches your objectives.