In 2005 I completed a dissertation on the effectiveness of safety awards on reducing at-risk behaviors. Although not primarily directed at safety, I was surprised to learn that there is a goodly amount of literature on the subject; particularly within the behavioral sciences.
Safety awards and incentives can successfully promote safe work behaviors, but they should never be used as a carrot. The more desirable the carrot, the more likely employees will under report.
On the other hand, awards that recognize employees for their safety effort or for attaining certain performance goals have shown to be quite successful, particularly if they are unannounced and unexpected.
With Kind Regards,