SPRINGFIELD -- The FBI released its annual Crime in the United States report this week, and the agency's data for Springfield show that in 2012 the city saw its second-lowest violent crime rate of the past 28 years.

According to the FBI's dataset, a total of 1,606 violent offenses were recorded in Springfield in 2012. That number translates to a rate of 1,039.4 violent offenses per 100,000 residents -- a rate that is the city's second-lowest recorded since 1985, coming in just behind the 2011 rate of 1,027.3 violent crimes per 100,000 residents.

The city's total number of violent offenses in 2012 represents a 1.5 percent increase from the 2011 total of 1,582. The city's violent crime rate, according to FBI data, peaked in 1997 with 3,075.5 offenses per 100,000 residents.

Property crime, meanwhile, decreased 4.6 percent in the city from 2011 to 2012, outpacing a national drop of .8 percent.

The Uniform Crime Report program, which supplies the numbers for the Crime in the United States report, draws data from roughly 17,000 law-enforcement agencies across the nation. The data include totals for violent and property crimes, as well as for individual offenses within those two categories. Rates in this post calculated as the number of offenses per 100,000 residents.

Below, I've created a graphic showing overall rates of violent and property crime in Springfield from 1985 to 2012, as well as rates for the individual offenses.

Before we get to the graphic, though, here are a few reminders about the FBI's data:

The FBI advises against comparing or ranking cities.

In the wake of this report's release, you'll see a lot of media outlets produce lists of "Most Dangerous Cities" or "Most Violent Cities". That's despite the fact that the FBI warns that such rankings:

You can read the

FBI's full "Caution Against Ranking" here

.

As a quick illustration of one of the flaws inherent in using the FBI data to rank communities, consider two fictitious cities. Imagine that City A has 100,000 residents and, in one year, records 10 homicides and 550 robberies. City B, meanwhile, has 100,000 residents and records 500 homicides and 10 robberies that year.

Which city ranks higher on a "Most Violent" or "Most Dangerous" list? Well, it's City A, with its higher violent crime rate -- despite the fact that 490 more people lost their lives to violent crime in City B.

Using the raw FBI numbers to calculate violent crime rates weighs all offenses equally, and it doesn't offer insights into the true nature of a crime problem within a city. The example above describes two cities with vastly different crime trends which will require vastly different public safety and public health approaches. But, the aggregate rates media outlets use to rank cities miss that type of nuance.

FBI data do not measure how "dangerous" a city is.

The data tables issued by the FBI are labeled "Offenses Known to Law Enforcement". Those offenses -- eight total -- are broken down into violent crime (murder and non-negligent manslaughter, forcible rape, robbery, and aggravated assault) and property crime (burglary, larceny-theft, motor vehicle theft, and arson*).

A number of offenses, including drug crimes, are not included in the dataset. Crimes that are not reported to police -- and, crimes that are not witnessed or otherwise detected by police -- are also not counted. That means there are natural discrepancies between the numbers presented by the FBI and the actual level of crime in a community.

The numbers, then, offer insights into the number and rates of eight distinct offenses, and those eight offenses only.

The "Most Dangerous Cities" lists you'll see circulating this week are typically calculated by ranking cities according to their overall violent crime rates -- that is, by adding up the city's total counts of murder and non-negligent manslaughter, forcible rape, robbery, and aggravated assault, dividing that sum by the city's population, and then multiplying by some baseline population total -- usually 1,000, 10,000 or 100,000.

But calculating the true "danger" of any given city would be an extremely difficult task, requiring the analysis of many more variables than those four offenses listed in the FBI's violent crime category.

That's because violent crime isn't the only thing that poses a danger to the public. Also dangerous: tornadoes, hurricanes, and other severe weather; sinkholes, mudslides, and forest fires; house fires; car crashes; poor electrical code enforcement; communicable diseases; sharks, bears, some spiders, some snakes, and potentially lots of other animals; missing manhole covers; etc.

The FBI's data do not measure any of those things.

So, what is the Uniform Crime Report data good for?

In a 2011 interview, criminology professor Christopher Kudlac told me: "[W]hat the (Uniform Crime Report) really is intended for -- and why law enforcement and public officials should look at it, is that it's a good measure of a trend within the city."

Kudlac, who teaches at Westfield State University, said that if a trend line shows crime increasing in a city, "Well, that says something -- that the police are noticing or detecting more crime." Or, that residents are more willing to report crime in their neighborhoods.

With all of that in mind, here's a look at the FBI's compilation of violent and property crime data supplied by the Springfield Police Department, from 1985 to 2012 (mouse over data points to activate pop-up windows):

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Finally, a few notes about Springfield's numbers:

Aggravated assault appears to be the driving force in changes in the violent crime rate over time. In 1997 -- the city's peak violent crime rate -- the rate for aggravated assault was 2,699.5 per 100,000 residents. In 2012, that rate was 656.2.

Motor vehicle theft is a major factor in changes in the city's property crime rate over time. Property crime peaked in the city in 1991, when the rate of motor vehicle thefts recorded per 100,000 residents was 2,376.5. In 2012, there were 491.9 incidents per 100,000 residents -- the only year in this time frame that the rate has fallen below 500.

Even comparing a city to itself over time isn't a perfect approach. A law enforcement agency's procedures for record keeping and classifying crimes can change over time, leading to fluctuations in the number of offenses recorded. Moreover, the Uniform Crime Report follows a "hierarchy rule" -- when an incident involves multiple offenses (e.g., a homicide committed during a robbery), only the most serious offense is counted. The numbers also offer only so much information about the offenses themselves -- the aggravated assault and robbery totals, for example, don't indicate whether violence involving guns or knives is increasing or decreasing. And, to reiterate, these numbers reflect only "Offenses Known to Law Enforcement" -- they don't capture crimes that go unreported.

Based on these numbers, what questions do you have? Are there trends you would like to see us follow up on by interviewing local law enforcement officials?

Please post your thoughts and questions to the comments.