Also, Papps (2008) considers whether a player’s performance is impacted by his teammates’ performance in that same season or in a previous season in order to determine the type of influence teammates have on one another. Papps distinguishes between two possible sources of influence. On the one hand, a player may be impacted by transitory spillovers from other players; for example, a pitcher’s winning percentage is positively related to the team’s offensive ability. Papps refers to this type of influence as statistical “inflation.” The alternative is that the player may learn from other players affecting their performance permanently. Papps finds evidence for both types of influence by tracking when the change in a player’s performance occurs.