This appendix offers a summary description of the data sources and, where applicable, data collection procedures for the six major data series presented in this book: death row inmates, death sentences, executions, exonerations, homicides, and net support. We employ annual measures of each of these variables as well as quarterly measures of the last four. Complete datasets for these series are available at the Web site associated with this book. Additionally, throughout this book we refer to several data sources beyond these six major series. We provide citations for those data sources in notes throughout the text.

DEATH ROW INMATES

Annual Measure, 1953 to 2006: This series gives the total number of individuals under sentence of death in the United States in each year. We follow the Death Penalty Information Center in supplementing the primary Bureau of Statistics data source with the NAACP estimate for the most recent year as follows: 1953 to 2005 data from Snell 2005 (Figure 1: Persons under Sentence of Death 1953 to 2005); 2006 data from Fins 2006 (Table: Total Number of Death Row Inmates Known to LDF [Legal Defense Fund]).

DEATH SENTENCES

Annual Measure, 1961 to 2005: This series gives the number of death sentences handed down each year as provided by the following sources: 1961 to 1972 data from National Prisoner Statistics 1974; 1973 to 2005 data from Snell 2005 (Appendix Table 2: Prisoners Sentenced to Death and the Outcome Sentence, by Year of Sentencing, 1973 to 2005).