The determinants of sentencing are of much interest in criminal justice and legal research. Understanding the determinants of sentencing decisions is important for ensuring transparent, consistent, and justifiable sentencing practice that adheres to the goals of sentencing, such as the punishment, rehabilitation, deterrence, and incapacitation of the offender, as well as reparation for the victim. It is important to frame research questions on sentencing that can feasibly be answered by appropriate research methods, within the constraints of limited time and resources. For illustration, this article presents three methodological approaches for investigating the factors that may influence sentencing decisions: multilevel analysis using existing sentencing data; sampling of, and data collection from, sentenced court case files; and experimental designs involving sentencers deciding on hypothetical cases. The strengths and weaknesses of each approach are compared and discussed. (Contains 6 notes, 5 tables, and 2 figures.)