This study collection sought to thoroughly understand the creation, testing, and use of forensic science in five jurisdictions across the country. A random sample was selected of recent criminal cases in the following jurisdictions and tracked from investigation to adjudication to understand how forensic evidence functions: Sacramento County, CA: 990 cases Segwick County, KS: 936 cases Allegheny County, PA: 978 cases Bexar County (San Antonio), TX: 936 cases King County, WA: 892 cases The Principal Investigator sought answers to the following seven primary research questions: How often is forensic evidence collected and analyzed and how is it used pre-arrest? What are the outcomes of forensic evidence testing? What is the effect of forensic evidence on arrest and charging? How does forensic evidence affect the plea-bargaining process? What effect does forensic evidence have on conviction and sentencing outcomes? Does the turnaround time for analysis of forensic evidence have any impact on case disposition? Does the institutional configuration of the crime laboratory have any effect on its productivity? Data for the following types of forensic testing are included in this data collection: hair, fibers, glass, paint, gas chromatography / mass spectrometry (GC/MS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy / energy dispersive x-ray spectroscopy (SEM/EDX), physical match, drug identification, toxicology, serology, combined DNA index system (CODIS), DNA short tandem repeat (Y-STR), blood pattern, test fire, and comparison scope.