City-Data Forum How does city-data calculate its crime index?
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06-26-2007, 06:24 PM
 8,376 posts, read 26,720,095 times Reputation: 2340

I was curious as to how city-data calculates its safety index. I wanted to calculate the index of crimes in my entire county CD style, rather than on city level. I found a website that gave me all of the information. Thank you very much .

06-26-2007, 09:12 PM
 Location: Blue Ridge Mtns of NC 5,661 posts, read 23,727,925 times Reputation: 3752
They probably get the county level crime data from the FBI's annual Uniform Crime Reporting (UCR) Program. The final 2006 FBI report hasn't been issued.

Florida Counties - Table 10 (Florida) - Crime in the United States 2005 (http://www.fbi.gov/ucr/05cius/data/table_10_fl.html - broken link)

06-26-2007, 09:16 PM
 8,376 posts, read 26,720,095 times Reputation: 2340
Quote:
 Originally Posted by mm34b They probably get the county level crime data from the FBI's annual Uniform Crime Reporting (UCR) Program. The final 2006 FBI report hasn't been issued. Florida Counties - Table 10 (Florida) - Crime in the United States 2005 (http://www.fbi.gov/ucr/05cius/data/table_10_fl.html - broken link)
Florida has issued thier stats

Statistics compiled by the FDLE for crimes in Florida -- OrlandoSentinel.com

I am just trying to figure out if thier crimes per 100,000 index is similar to that of City-Data. If it is, my city took a HUGE jump this year! I want to calculate my own index CD style, but I am struggling to find out how they do it, I have tried all sorts of calculations. If i knew what crimes per 100,000 was relevant to the national average, I could just rely on that, but its pretty difficult without benchmarking it to anything.

Also, that link is just revealing data about county police offices. Although BSO (my area) may have only handled three murders, most cities have an independent police department, so obiously my county of 1.8 million had more than that!

06-26-2007, 09:21 PM
 Location: Blue Ridge Mtns of NC 5,661 posts, read 23,727,925 times Reputation: 3752

Federal Bureau of Investigation - Uniform Crime Reports

06-26-2007, 09:24 PM
 8,376 posts, read 26,720,095 times Reputation: 2340
I apperciate the link, but I am still curious as to how CD calculates its index to get the number that they have.

06-28-2007, 01:47 AM
 122 posts, read 341,225 times Reputation: 57
You take the number of murders, multiply by 4, add arson multiplied by the square root of thefts, use a random number generator to get a value from 1-100 and add that to burglaries.

Then, you add all those numbers together. Take the population of the city, and divide by that number.

* If it's more than 300, you put it in the "high crime" category, and use a random number generator to add anywhere from 1-100 to it. If it's less than 40 miles from a town of between 2000-3000 people you add the last two digits of that town's population. You add the number of rapes per 100,000 people, and a number you fancy that's less than 200. Add the number of movie stars in the area times the current day of the month. Then you subtract the number of adult novelty shops, drug dealers, and prostitutes in the city from the total. If the final number is less than 1000, or the city is D.C. that's your crime index. If it's more than 1000, you subtract the number of Elvis sightings in the county in the last 40 years from the total.

* If the number was less than 300, you throw three darts at a dart board and multiply your score by 2. Whichever number is bigger is the crime index. If both numbers are zero, add 40 to the number of weeks it is until your birthday to get the index.

Hope that helps!

07-03-2007, 02:40 PM
 8,376 posts, read 26,720,095 times Reputation: 2340
I hate to be lazy but...

2006 Florida County-by-County Crime Data -- OrlandoSentinel.com

Can Broward be calculated?Orange? Palm Beach? Miami-Dade? Heh.

07-09-2007, 11:24 AM
 8,376 posts, read 26,720,095 times Reputation: 2340
Quote:
 Originally Posted by fort lauderdale I hate to be lazy but... 2006 Florida County-by-County Crime Data -- OrlandoSentinel.com Can Broward be calculated?Orange? Palm Beach? Miami-Dade? Heh.
Wah wah wah, I guess nobody passed algerbra!!!!

12-24-2009, 07:20 AM
 Location: Lancaster, TX 1,430 posts, read 3,158,138 times Reputation: 2018
I see the Crime Index Scores have been updated to include 2008 statistics based on the latest FBI Uniform Crime Report. When calculating the final index score, are any types of crime weighted more that others in the tally? My reason for asking is that some of the new figures for cities in my area (Dallas-Fort Worth) show places with higher per capita property and violent crime rates are receiving lower "better" scores than places with lower per capita rates.

Here's one example:

Garland (pop. 219,135)
2008 Violent Crimes: 773 (352.8 crimes per 100,000 population)
2008 Property Crime Rate: 9,241 (4217.0 crimes per 100,000 population)
2008 Total Crimes: 10,014 (4569.8 crimes per 100,000 population)
2008 City-Data Crime Index Score: 328.8

Mesquite (pop. 132,600)
2008 Violent Crimes: 492 (371.0 crimes per 100,000 population)
2008 Property Crime Rate: 6,126 (4619.9 crimes per 100,000 population)
2008 Total Crimes: 6,618 (4991.0 crimes per 100,000 population)
2008 City-Data Crime Index Score: 324.8

There are other examples in my area as well. Any explanation or insight would be greatly appreciated.

Thanks!

12-24-2009, 11:41 AM
 Location: Illinois 3,096 posts, read 2,177,111 times
Not all violent and property crimes are given equal weight. For example, a murder is given more weight than an assault.
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