The collection of high-quality crash data, and its quantitative analysis to discover trends and factors associated with different crash types, is a critical skillset for the modern safety professional. This module provides an overview of the important considerations that must be made when collecting safety data and using it for policy decisions, or for quantitative analysis in crash modification factors (CMFs) and safety performance functions (SPFs). The specific areas covered include safety data basics, ensuring the collection of quality safety data, crash frequency and severity factors, and basic quantitative safety analysis.