Crime rates are not static. They rise, fall, spike, and decline over years and decades, driven by forces that range from demographic shifts to policing strategies to economic conditions. Understanding why crime rates change is essential for interpreting current data and anticipating where a city might be headed. This guide examines the major forces behind crime trends, drawing on FBI data from 248+ cities.
The Great Crime Decline: 1991 to 2019
The Great Crime Decline is one of the most significant social trends in modern American history. From the peak in 1991, the national violent crime rate fell by approximately 50% over the next two decades. Property crime declined by roughly 60%. This was not a localized phenomenon — it occurred across nearly all crime categories, in cities of all sizes, and in every region of the country. The murder rate dropped from 9.8 per 100,000 in 1991 to about 5 per 100,000 by 2014.
No single explanation fully accounts for the decline. Leading theories include the end of the crack cocaine epidemic, demographic aging (fewer young men in peak offending years), increased incarceration, innovative policing strategies like hot-spot policing and CompStat, economic growth, reduced lead exposure, and better security technology. Most criminologists believe multiple factors worked simultaneously. The important takeaway: even cities with rates above the current national average may be dramatically safer than they were 25 years ago.
The 2020-2021 Disruption
After nearly three decades of decline, several crime categories spiked in 2020. The national murder rate increased by approximately 30% in a single year — the largest one-year increase on record. Aggravated assault and gun violence also rose. However, property crime overall continued to decline, and the increase was heavily concentrated in specific cities and neighborhoods. Researchers have linked the 2020 spike to pandemic disruption (economic stress, social isolation, reduced community programming), changes in policing practices, court closures that delayed case processing, and other cascading effects of an unprecedented year. Critically, by 2022-2023, many of the cities that experienced sharp increases began to see significant reversals.
What Drives Crime Rates Up
Research identifies several consistent factors associated with rising crime rates. Economic distress — particularly concentrated poverty, youth unemployment, and income inequality — correlates strongly with crime increases. Drug market disruptions (the introduction of a new drug or supply chain changes) can trigger violence. Reduced police staffing or changes in enforcement strategy can affect deterrence. Community disruption (mass displacement, housing instability, breakdown of social institutions) removes the informal social controls that normally suppress crime. And seasonal patterns mean that summer months consistently produce higher crime than winter.
Currently rising: Federal Way, WA (+9.0%), Chesapeake, VA (+9.0%), New York, NY (+9.0%) have seen the largest 5-year increases in our database.
What Drives Crime Rates Down
The factors associated with declining crime rates are often the inverse of those that drive increases, but not always symmetrically. Economic improvement helps, but crime reductions can also occur during recessions if other factors are favorable. Evidence-based policing strategies — particularly hot-spot policing, community policing, and focused deterrence — have strong research support for reducing violent crime. Environmental changes like improved CPTED design (better lighting, clear sightlines, maintained spaces) reduce opportunity for crime. And demographic shifts — particularly the aging of the population past peak crime years — have been a consistent downward force.
Getting safer: Pueblo, CO (-15.0%), Modesto, CA (-15.0%), Pasadena, CA (-15.0%) have seen the largest 5-year declines.
Why City-Level Trends Diverge From National Trends
National crime trends are averages — and averages can mask enormous variation. During any given period, some cities will be getting dramatically safer while others are getting worse, even as the national average moves modestly in one direction. Local factors — a new police chief with different strategies, the closure of a major employer, demographic shifts driven by migration, changes in the housing market, or the arrival or departure of organized criminal activity — can all cause a city's trend to diverge sharply from the national picture. This is precisely why CrimeContext tracks trends at the city level rather than relying on national averages. The national average tells you where the country is headed; the city-level trend tells you where your community is headed.
How to Interpret Trend Data on CrimeContext
Every city page on CrimeContext shows a 5-year trend calculated as the percentage change in total per-capita crime rate. A negative number means crime has decreased; a positive number means it has increased. The trend carries a 20% weight in the Safety Context Score. When evaluating trends, keep several things in mind. First, percentage changes in small cities can be volatile — small absolute changes produce large percentage swings. Second, a city rebounding from a 2020 spike may show improvement even if it has not returned to pre-2020 levels. Third, trends in violent crime and property crime can move in opposite directions, so check both. And fourth, the most reliable trends are sustained, multi-year patterns — not one-year jumps.
Key takeaway: Crime trends are driven by real, identifiable forces — not random chance. Understanding those forces helps you distinguish between cities on a positive trajectory and cities where current problems may persist. Look for multi-year patterns, not headlines about single-year changes. And always check whether a trend reflects genuine change or simply a reversion to a prior level after an anomalous spike.