My study examines why Supreme Court justices choose to author their own opinions when either concurring or dissenting in a given case. I analyze ideological differences, time constraints, vote margin, lower court disagreement, precedent alteration, seniority, age, and experience to help discern justices' motivations for not only joining a dissent or concurrence but actually writing one. The expansive nature of the data used is unprecedented in the literature and will provide a substantial contribution.