This dissertation studies issues associated with various topics related to a worker’s effort. For example, I explore how different wage incentives affect a worker’s productivity. I explore how exogenous shocks, what we often refer to as “luck,” can affect a worker’s motivation. In addition, I explore how different wage contracts destroy cooperation and can lead to destructive activities such as cheating and sabotage, as well as how these activates, in turn, affect productivity. Finally, in the last chapter, I analyze behavioral issues related to fairness and altruism in tournaments, and how these behaviors affect worker’s effort.