Clarifying gun policy requires people working from consistent and credible data. Below are the most common sources for criminology, health and other databases used by policy researchers.
FBI Uniform Crime Statistics: http://www.ucrdatatool.gov/
Injury and Death
Center for Disease Control Injury Prevention & Control: Data & Statistics (WISQARSTM): http://www.cdc.gov/injury/wisqars/
California Department Of Justice, crimes and crime clearance statitics: http://oag.ca.gov/crime/cjsc/stats/crimes-clearances
Timeline for California gun control laws: http://wiki.calgunsfoundation.org/Time_Line_of_California_Firearms_Laws
Clearance: The percentage of crimes for which charges against a defendant are made or otherwise adjudicated. “Clearance rate is calculated by dividing the number of crimes that are “cleared” (a charge being laid) by the total number of crimes recorded.” http://en.wikipedia.org/wiki/Clearance_rate