State supreme courts use a number of approaches to comparative proportionality sentence reviews. One approach is to rely on generalized notions of reasonableness, based on the court's own values, experience, and general familiarity with prior cases. The court may take a precedent-seeking approach and identify the relevant aggravating and mitigating factors, make a judgment regarding the proportionality or excessiveness of the sentence based upon those factors, and identify one or more comparable cases that support its decision. Factors that should be used in comparing cases are discussed, and cases that should be considered in conducting proportionality reviews are examined. The issue of how a State with a new death penalty statute should decide the proportionality of the first case is also addressed. A proportionality review questionnaire prototype is included, as are manual and automated similar case selection systems for use in conducting comparative proportionality reviews in death sentence cases. Examples of program reports are provided, along with system, program, and file cross-reference documentation. Program input and output flow charts are supplied, and file layouts and file usage forms are presented. Program listings for a case selection system are provided, along with 41 references.