Monday, February 24, 2014

Eat, breathe, and sleep the 60 Steps

One of the most useful things a crime analyst can do for their department is to become a problem solver. What I mean is that crime analysts should be the first ones to identify crime problems in the community they serve. While being a clarion and sounding the alarm is important, a crime analyst becomes far more useful when they not only identify a crime problem, but they help shape the strategy to solve it. In fact, a whole policing methodology has developed from this idea. That methodology is called Problem Oriented Policing.

But just what is Problem Oriented Policing? Professor Herman Goldstein described it this way:
“Problem-oriented policing is an approach to policing in which discrete pieces of police business (each consisting of a cluster of similar incidents, whether crime or acts of disorder, that the police are expected to handle) are subject to microscopic examination (drawing on the especially honed skills of crime analysts and the accumulated experience of operating field personnel) in hopes that what is freshly learned about each problem will lead to discovering a new and more effective strategy for dealing with it. Problem-oriented policing places a high value on new responses that are preventive in nature, that are not dependent on the use of the criminal justice system, and that engage other public agencies, the community and the private sector when their involvement has the potential for significantly contributing to the reduction of the problem. Problem-oriented policing carries a commitment to implementing the new strategy, rigorously evaluating its effectiveness, and, subsequently, reporting the results in ways that will benefit other police agencies and that will ultimately contribute to building a body of knowledge that supports the further professionalization of the police.”
One thing I really want to accomplish with my posts this year is to provide guidance for those crime analysts that may have been placed in the job with little or no formal training. When I was planning the series I contacted a number of crime analysts about my idea. I was really shocked by the number of responses I got from crime analysts who said that they never received formal training when they started their career. I even had one that told me she was working in a clerical position in her department and one day her Chief walked in and told her she was now her agency’s crime analyst! While this isn’t the best way to bring a crime analyst on board, it is sometimes a reality.
It is my belief that becoming a problem solving crime analyst is one of the most important things an analyst can do to make a difference at the agency where they work. Identifying (scanning), analyzing, formulating a response and then assessing your effectiveness is the SARA model which is the heart of Problem Oriented Policing.
Ronald Clark and John Eck wrote a book for the University College London’s Jill Dando Institute of Crime Science. The book was titled Become a Problem Solving Crime Analyst in 55 Small Steps. This book was later revised and slightly expanded for US law enforcement as Crime Analysis for Problem Solvers in 60 Small Steps.
Regardless of which version you prefer, you really need to get one of these books. In the welcome or “Read This First” section of the book it has this statement:
“This 60-step manual assumes that you are an experienced analyst and that you are accustomed to providing the kind of information needed to support police operations.”
It then goes on to list a number skills that an “experienced” crime analyst has. If you’re a new crime analyst or haven’t mastered all (or any) that list of skills don’t let this warning scare you away. There is still a lot this book has to offer you. In fact, very few of those skills are needed to digest the 60 steps.
To show you how important I think the 60 Steps are to crime analysis, back in 2009 (and again in 2012) I went through each of the 60 Steps in a series of posts here on The Crime Analyst’s Blog. You can go through those posts here.
Here’s one of the best things about the 60 Steps. You can get the book free as download or even order a bound copy for free. There is also an online version. I believe that every crime analysis unit should have a copy of this book and every crime analyst should read it.
This brings up a related tip, as a crime analyst you need to set aside a regular part of your workweek for professional reading. Shut down the email client, turn down the ringer on the phone and shut your office door if you have to but spend time learning the craft of crime analysis. If you need something to read the Problem Oriented Policing Center’s website has plenty of great material to keep you busy and it’s all completely free.
What are you waiting for?

Monday, February 17, 2014

Crime Patterns, Crime Sprees, and Crime Series

One important job for crime analysts is reviewing crime reports that come into your agency. Every  morning one of the first things I do is review the reports submitted by our officers for the previous day. When I first started as a crime analyst, I was able to review every arrest report and every incident report that came in. Now that the community where I work has grown, the number of crime reports has grown too. However, while I don’t get the opportunity to read each and every report, I do hit all the important ones. 

When I review these reports I’m looking for a number of things. I am looking for reports that may be of concern to my Chief or our city government. I am looking for reports that may indicate an emerging crime threat to the community. Most importantly I am looking for reports that may be related to previous cases. Every report that you get is another piece of information that could help you clear that case. 

There are a number of ways that crimes can be related to each other. Understanding these relationships can help you determine the relevance of these subsequent cases and help you determine a strategy for using the information they contain. Multiple crime reports can document a crime pattern, a crime spree or a crime series. 

The International Association of Crime Analysts has a white paper that standardizes the definitions of these terms. 

“A crime pattern is a group of two or more crimes reported to or discovered by police that are unique because they meet each of the following conditions:

1. They share at least one commonality in the type of crime; behavior of the offenders or victims; characteristics of the offender(s), victims, or targets; property taken; or the locations of occurrence;
 2. There is no known relationship between victim(s) and offender(s) (i.e., stranger-on-stranger crime);
3. The shared commonalities make the set of crimes notable and distinct from other criminal activity occurring within the same general date range;
4. The criminal activity is typically of limited duration, ranging from weeks to months in length; and
5. The set of related crimes is treated as one unit of analysis and is addressed through focused police efforts and tactics.” 

One of the most dramatic types of crime patterns is the crime spree. These sprees are the types of crimes that often make the news. A criminal robs a store, then carjacks someone in the parking lot to obtain a getaway vehicle and soon gets into a vehicle pursuit with police, he crashes the car and then takes someone hostage.  Sprees are a group of crimes committed by the same actor or group over an extremely short period of time. Dramatic, but often one that isn’t terribly worrisome to a crime analyst with the exception of making sure that all the potential crimes and victims are identified so they can be handled appropriately. 

Another type of crime pattern has several different but related definitions. The are Hot Prey, Hot Product, Hot Spot, Hot Place and Hot Setting. They are related in that these crimes all have a similarity whether it is a type of victim, targeted product, proximity, a specific location or environment. Criminals that targets only immigrant families for home invasion robberies would be a Hot Prey. Thieves that target iPhones for theft is a Hot Product pattern. Burglars that targets homes in the same neighborhood is a Hot Spot. A Hot Place may a bar that has numerous assaults, vehicle burglaries in the parking lot and pickpocket thefts. And finally a Hot Setting may be robberies of convenience stores by different offenders. 

One of the most important things and analyst can do is to identify a crime series. These are similar crimes committed by the same offender or group of offenders as part of continuing series of events. What makes the identification of them so important is that if a crime series is identified and analyzed you can often times predict future events in these series with some degree of accuracy. Additionally, by putting all the pieces together from each crime in the series, you can gain a fuller picture of the offender responsible. Regardless of what type of crime pattern you identify, they are important to understand because they each lend themselves to specific tactics deal with them. 

What types of crime patterns have you identified in the reports that come into your agency?

Monday, February 10, 2014

Introduction to Pivot Tables

Every now and then you make a discovery that turns out to be mindblowingly wonderful. They don’t happen often but when they do, they are great. I made one of those discoveries one day shortly after I became a full time crime analyst.

As a beginning analyst I quickly found that while it was pretty easy to get data out of a database it was a whole lot harder to analyze these records and turn them into something meaningful. I would export a bunch of records out of our records management system and pull them into a spreadsheet. But then when it came to operations like counting records meeting certain criteria I’d resort to sorting records into categories and either physically counting rows or using the row numbers to determine the number of records meeting my criteria. There had to be a better way.

As it turns out, there was. 

I was playing around in Microsoft Excel, the spreadsheet application we use at my office. I became curious about the “Insert Pivot Table” command. So I hit the F1 or Help key and looked up the help file entry for Pivot Table. This is what it said:

“A PivotTable report is an interactive tool that combines and compares data. You can rotate its rows and columns to see different summaries of the source data and display the details for areas of interest. Use a PivotTable when you want to analyze related totals, especially when you have a long list of figures to sum and you want to compare several facts about each figure. Because a PivotTable is interactive, you can freely experiment with layout of the data to focus on specific details or calculate different summaries, such as counts or averages.”

That sounded exactly like the tool that could make my life easier when it comes to analyzing the data I extracted from our records management system. 

A Pivot Table helps you take a table full of records like this:

and turn it into something like this with just a few mouse clicks.

The real beauty of a Pivot Table lies in that last sentence from the help file description:
“Because a PivotTable is interactive, you can freely experiment with layout of the data to focus on specific details or calculate different summaries, such as counts or averages.”

Interactivity is what really gives a Pivot Table power. It’s pretty easy to create a report in an application like Crystal Reports that will spit out a count of the number of burglaries you had in a given month. But what if as you are analyzing the data you notice that a large number of those burglaries appear to be happening at apartment complexes. 

You can go back and filter out all the burglaries at different types of locations and then re-run the report one at a time or by using the interactivity of a Pivot Table you can drop the Location Type field into your Pivot Table and quickly parse out the numbers of burglaries at all different types of locations. A couple of clicks and you’re looking at a lot of different facets of your dataset. Don’t find the answer you’re looking for, add or remove different fields to look at the data another way. 

Want to know the day of the week frequencies of those apartment burglaries?  Throw the Day of Week field in the mix and within in the space of a few minutes you are determining what day is most common for apartment complex burglaries. 

There are a bunch of online tutorials on how to create and use Pivot Tables. Here’s a text based one from Microsoft. There are also You Tube videos and other websites that can teach you how to be really proficient with them. There is also an excellent book by Mark Stallo and Chris Bruce of the International Association of Crime Analysts called Better Policing with Microsoft Office 2007 that can help you wring the most out of Microsoft Office. It includes a section on Pivot Tables. 

What data could you understand better with a Pivot Table?

Monday, February 3, 2014

How to calculate crime rate

One question I get all the time is “What’s the crime rate?” However, most of the time when people ask that question they don’t really understand the question they are asking. When citizens call my office and ask “What’s the crime rate?” they are usually asking it in relation to a particular neighborhood. The community where I work is right next to a large military base so we have people moving in and out of the community on a regular basis. What they usually mean is “I want to know if the neighborhood where I am considering purchasing a house is safe?” The answer to that one is complex. They ask about crime rate because they hear the term used in the media and think it will tell them something about the community.

The strict definition of mathematical rate is: “is a ratio between two measurements with different units”. Calculating Rate is a way of normalizing between different units. Crime rate is the number of crimes that occur in a given population. Let’s look at it this way.

  • Community A has a population of 50,000. Last year they had 5 murders. 
  • Community B has a population of 5,000. Last year they had 2 murders. 

Which community had a bigger problem with murders last year? Calculating the crime rate can help us normalize the populations between these two very different sized towns.

Crime rate is normally expressed as the number of crimes per 100,000. In order to calculate this the formula would look like this:

(Number of Crimes / Population) x 100,000 = Crime Rate Per 100,000

Remember your order of operations. You need to do the part of the equation enclosed in parenthesis first. Now let’s look at our two communities and see what their murder rate is.

Community A

(5 / 50,000) x 100,000 = 10 murders per 100,000 population

Community B

(2 / 5,000) x 100,000 = 40 murders per 100,000 population

This is quite the difference. Community B’s murder rate is four times greater than Community A even though Community A had three more murders than Community B. Of course this brings up a whole other discussion on whether it’s fair to directly compare crime statistics in two different communities. The FBI has a warning on their Uniform Crime Reports site that goes into detail about why this isn’t a good practice. However, rates can also be used to compare a city against itself at different times to account for a population growth or decline.

For instance, the community where I work is consistently listed as one of the 10 fastest growing areas of the United States. When I started my law enforcement career in 1991 the population of Killeen, TX was around 57,000. Now, 23 years later the population is over 134,000. Given than kind of population growth it’s a valid question to ask if we are doing better or worse in our crime suppression efforts now than we did back then. But you don’t have to limit calculating rate to just crimes. You can use this to normalize traffic accidents, citations, arrests, calls for service or any other metric.

What metric could you understand better by calculating it’s rate?