20161031-dashboard-screenshot

We’ve created a crime dashboard to help us understand the crime situation in West Hollywood, Beverly Hills, Culver City, Santa Monica, and 459 other California cities.

A dashboard is a visual tool that gathers and presents several important pieces of information in one place. In a car, the dashboard gathers information about speed, fuel level, engine temperature, etc. We might call these “key performance indicators” for a car. They indicate how well the car is operating. The driver needs to know if the speed or the temperature is too high or if the fuel level is too low. The driver gets the information visually through the speedometer, fuel gauge, temperature gauge, etc.

Similarly, our dashboard gathers information about crime in a particular city. It has “key performance indicators” that show how successful the city has been in limiting crime. The information is presented visually through a series of graphs and tables.

Click here to see the crime dashboard. Like the dashboard of a new car, it can take a few minutes to familiarize oneself. Data for West Hollywood comes up first, but you can pick a different city from the drop-down list in the first rectangle.


Performance indicators

Most of the dashboard’s performance indicators are based on an adjusted version of the crime rate. For each city, the dashboard shows:

  • Overall level of crime
  • Increase or decrease over time
    • Crime trend
    • Change in crime over different timeframes
  • Level of crime by comparison
    • Crime compared to nearby communities
    • Crime compared to all California cities
  • Type of crime
    • Count and frequency by type of crime
    • How the types of crime differ from the California average


Crime rate adjusted for seriousness

The crime rate is the most common way of comparing crime across jurisdictions and time periods. The FBI and the State of California both use it. It is the number of violent and property crimes reported in a year, divided by the population. It is often expressed as “crimes per 100,000 people,” but we’re using “crimes per 10,000 people,” because most California cities have fewer than 100,000 residents.

We can improve the crime rate as a performance measure by taking into account another critical factor: the seriousness of the underlying crimes. Policymakers and the public react differently to the volume of crime depending on the type of crime. Aggravated assaults or robberies — or worse — matter more than petty thefts or car break-ins.

Our dashboard adjusts the crime rate to capture those differences in seriousness. We picked California in 2014 as the standard. If a city’s mix of crime is more serious than it was in California in 2014, then the dashboard adjusts the crime rate up by the same percentage. If a city’s mix is less serious, the dashboard reduces the crime rate.

The dashboard needs a measure of seriousness. We decided to use prison sentences set by the California legislature. We had to pick a specific offense to represent each type of crime (e.g., second-degree murder for homicide) and a sentencing level for that offense (e.g., the bottom end of the 15-years-to-life sentence for second-degree murder).


Workers and visitors

Neither the crime rate nor our adjusted crime rate takes into account differences in the number of workers or visitors. Ideally, we would adjust for that, but the dashboard can’t do it yet. As you use the dashboard, please keep those differences in mind. They may partly or fully explain higher crime rates in some cities.


Estimates

Our primary data source goes through 2014. We also prepared 2015 and 2016 estimates for selected cities, plus 2016 estimates for selected Los Angeles neighborhoods. We used numbers from city websites and the Los Angeles Times.

We extrapolated from partial-year 2016 to full-year 2016 by assuming that crime rates would stay the same. For example, if we had numbers through August, we divided them by eight and multiplied them by 12. We handled the City of Los Angeles a little differently, because of the larger numbers. We assumed that crime in full-year 2016 would increase by the same percentage from full-year 2015 that partial-year 2016 had grown from the same period in 2015.

To calculate seriousness for 2015 and 2016, we needed more detail than the city websites or Los Angeles Times provided. So we used the detail from 2014 for each city. We assumed that armed robberies made up the same percentage of all robberies that they had in 2014, that residential burglaries were the same share of all burglaries, and that higher-dollar thefts were the same proportion of all thefts. We also assumed that arsons were the same percentage of violent and property crimes.


Sources

Our sources were:

  • California Office of the Attorney General (CJSC database) for crime data through 2014
  • City websites for more recent crime data
  • Los Angeles Times’ Mapping LA for crime and population data for selected neighborhoods in the City of Los Angeles
  • California Department of Finance for population estimates
  • Attorney websites for information on prison sentences


http://wehobythenumbers.com/wp-content/uploads/2016/11/20161031-dashboard-screenshot.jpghttp://wehobythenumbers.com/wp-content/uploads/2016/11/20161031-dashboard-screenshot-300x300.jpgDavid WarrenPerformance (effectiveness)Public safetybeverly hills,burbank,crime,culver city,glendale,los angeles,pasadena,san diego,san francisco,santa monica
We've created a crime dashboard to help us understand the crime situation in West Hollywood, Beverly Hills, Culver City, Santa Monica, and 459 other California cities. A dashboard is a visual tool that gathers and presents several important pieces of information in one place. In a car, the dashboard...