The Crime Index suggests the risk of certain types of crime occurring in this community as compared to the national average. The national average for each type of crime equals a score of 100, so a score of 200 would represent twice the risk as the national average, and a score of 50 would represent half the risk of the national average. Below is the Crime Index for ZIP code 23702 in Portsmouth Virginia.
Crime Risk Crime Risk is defined as the chance that a crime will be committed against your person or property when compared against every other ZIP code in the United States. This is not a count of the actual incidence of crime in an area. Risk indexes are useful in that they level the playing field in terms of the size of the location and the number of persons living in it.
For example, large cities will have a higher number of crimes in total than small towns. A simple reporting of the number of crimes in both places would not give you an accurate picture of their relative safety. However, by comparing the risk index values of several locations of interest you can quickly see, regardless of location size, how they compare in terms of actual risk of future crime.
OnBoard uses sophisticated statistical modeling methods based upon industry best practices in order to provide Crime Risk data. As with all statistics, there is a lag between collection and distribution from government sources.
What is a "100 base" index? The crime index is based upon a national average = 100. This means that places at or around an index value of 100 have approximately "average" crime risk for the US.
It should be noted that "average" risk is actually an indication of very low crime. Consider where you live, and cities you have visited, against how safe you felt or the number of times you have had a crime committed against you. Most people are not constantly in fear of being robbed or murdered. It is only in the places that have extremely high crime that one would generally feel unsafe.
What would be a typical "city" or "country" crime risk? As one might expect, crime risk is generally higher in urban environments. As a general rule of thumb, a typical densely populated urban areas might have twice the national average crime risk (200), while sparsely populated rural area might have half the national crime risk (50).
But I live in a very safe neighborhood. Why is the crime risk so high? There are several factors that might contribute to this:
Keep in mind that a crime risk of 150 does not indicate high crime and is very typical for cities - even in their safest neighborhoods.
ZIP codes often contain several disparate areas. Perhaps you live in a gated community, but there may be other areas included in the ZIP code. Some times, truck stops, highway corridors, commercial / industrial areas located in the ZIP code can have a negative effect on overall crime rates.
Neighborhoods are constantly changing. The risk indexes are based upon the most recent seven years of FBI crime reports. While the index is weighted more heavily toward the more recent reports, neighborhoods can change quickly with new development and population growth.
High income, affluent neighborhoods often demonstrate a high risk for property crimes such as motor vehicle theft and larceny.
What are the sources for this data? The risk index is based on extensive statistical analysis of the most recent several years of crime reports from the vast majority of enforcement jurisdictions nationwide. The primary historical source for this information is the FBI's Uniform Crime Report (UCR). Each year the FBI collects crime statistics for over 16,000 city, county and state law enforcement jurisdictions. Jurisdictional participation exceeds 95% annually. The current sources are the six most recent full UCRs as well as the two recent preliminary reports released by the FBI. Additional sources include local and regional law enforcement offices.
As with most governmental sources, the UCR report lags present day by two to three years. There may have been significant increases or decreases in crime risk in the intervening period. We encourage you to consult with a knowledgeable local Real Estate agent or contact the local police department for additional information.
How is the index actually calculated? Extensive statistical modeling was used to account for the general overall decline in crime throughout the US, eliminate local anomalies, and incorporate additional locally reported crime statistics. Thus, while crime has decreased nationally, our average crime risk remains 100, and areas that have seen crime declines equivalent to the national decline will not see changes in their relative risk rates.
Each of the seven crime types is modeled independently and different models exist for the seven geographic regions of the US. These models were applied to a fine level of geography (census block groups) and then modeled up to the zip code, place and county levels. These results were then weighted by population, aggregated to the national total, and then scaled to match the preliminary FBI crime estimates for the most recently available year.