"Each year when Crime in the United States is published, many entities-news media, tourism agencies, and other groups with an interest in crime in our Nation-use reported figures to compile rankings of cities and counties. These rankings, however, are merely a quick choice made by the data user; they provide no insight into the many variables that mold the crime in a particular town, city, county, state, or region. Consequently, these rankings lead to simplistic and/or incomplete analyses that often create misleading perceptions adversely affecting cities and counties, along with their residents. To assess criminality and law enforcement's response from jurisdiction to jurisdiction, one must consider many variables, some of which, while having significant impact on crime, are not readily measurable nor applicable pervasively among all locales. Geographic and demographic factors specific to each jurisdiction must be considered and applied if one is going to make an accurate and complete assessment of crime in that jurisdiction. Several sources of information are available that may assist the responsible researcher in exploring the many variables that affect crime in a particular locale. The U.S. Census Bureau data, for example, can be used to better understand the makeup of a locale's population. The transience of the population, its racial and ethnic makeup, its composition by age and gender, educational levels, and prevalent family structures are all key factors in assessing and comprehending the crime issue."
Federal Bureau of Investigation: http://www.fbi.gov/