 By using fixed effects regression analysis and taking into account the likelihood that a player would not retire at the end of his contract, this statistically significant boost occurs.Players inclined to retire generally show a lower OPS during their contract year since the financial incentive to boost performance is absent, whereas healthy, relatively young players seek a lucrative free agent contract and generally boost their production to garner the contract.Fixed effects regression modeling captures the changes in a player's performance relative to his past performance, thus capturing the changes in his behavior.