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.
The use of fixed effects regression analysis and consideration of the likelihood that a player will not retire at the end of their contract reveals a statistically significant increase in OPS. Players who are more likely to retire tend to have lower OPS during their contract year because they lack the financial incentive to improve performance. In contrast, healthier, younger players aim to secure lucrative free agent contracts and therefore boost their production.