In general, actions that are rewarded are actions that people attempt to take or execute. The prospect of rewards often encourages people and groups to take desired actions. A reward system establishes a link between desired behaviors/actions and rewards.

Effective reward and motivation management is challenging because "a reward system that delivers positive results in one organisation may have totally the opposite effect in another. Equally baffling is the fact that good reward systems require constant updating to remain effective and relevant."

from http://www.haygroup.co.uk