Whether exonerated or executed, defendants were defined as innocent only on the basis of compelling evidence that they were not involved in any element of the murder for which they were convicted. Independent variables related to these cases were identified through reference to the literature on the causes of wrongful convictions, as well as through an examination of the appellate records of these cases. Based on this information, researchers developed a data-collection instrument that was administered to respondents directly involved in these cases. In the cases of the executed defendants, the questionnaire probed respondents' views about the innocence claim and the factors that contributed to the original wrongful conviction and to the failure to detect this error prior to execution. Logistic regression analyses found that the following variables were significant predictors of case outcome (exoneration compared to executions): allegations of perjury, multiple types of evidence, prior felony record, type of attorney at trial, and race of the defendant. These findings identify significant problems with the administration of capital punishment that stem primarily from the quality of the case record created at trial. The postconviction discovery of new evidence was unrelated to case outcomes, suggesting that the absence of a developed trial record compromises the opportunity to reverse a wrongful conviction. This is confirmed by the finding that representation by private counsel at trial was significantly related to subsequent exoneration; whereas, the advantages of private counsel at appeal were not associated with case outcomes. 5 tables, 8 notes, and 71 references