Monday, December 5, 2016

Introduction to Link Analysis: Part 3 Link Analysis Diagraming

I originally wrote this post for a software company’s blog in 2014. This company was bought out and recently their blog and website have been removed from the web permanently. I am reposting it here for posterity. 

Two weeks ago I started a series of posts on Link Analysis. Link Analysis diagrams are used to explain the relationships between entities in a criminal investigation. There are three main types of diagrams that are part of Link Analysis. They are:

  • Time Event Chart
  • Association / Activity Matrix
  • Link Analysis Diagram

In this final post in the series, we're going to look at the last type of diagram, the Link Analysis Diagram. All the other diagrams build toward a Link Analysis Diagram.

Seven Steps of Link Analysis
Anacapa Sciences Inc. is one of the most well known groups teaching Criminal Intelligence Analysis to law enforcement in the United States. In their instruction they list Seven Steps of Link Analysis.

They are:

  1. Assemble all raw data
  2. Determine the focus of the chart
  3. Code an association matrix
  4. Code the associations in the matrix
  5. Determine the number of links for each entity
  6. Draw the preliminary chart
  7. Clarify and re-plot the chart

Time Event Charts, Association and Activity Matrixes are important to construct prior to constructing a Link Analysis Diagram. The analysis of the Time Event Chart, and matrixes will assist you in ensuring that your Link Analysis Diagram is accurate and complete.

Link Analysis Diagramming
While an Association Matrix indicates that a relationship exists between two or more persons, Link Analysis diagramming shows you what that relationship is.

Since your Link Analysis diagram may be seen by many persons it is important that your diagram conforms to certain established conventions. The US Army Intelligence Center describes it this way: “Standardization is critical to ensuring that everyone constructing, using and reading a link diagram understands exactly what the diagram depicts.” Your charts and diagrams are supposed to make things easier to understand, not harder!

Persons are depicted by an open circle with their name or alias inside.



Persons with an alias are depicted by overlapping circles with their name in one and the alias in the other.



Entities or events are depicted by a square or rectangle with the entity name inside.



A known link between two persons is represented by a solid line connecting the two.



A suspected link between two persons is represented by a dashed line connecting the two.



Conveyances are represented by a triangle.



Displaying a person’s membership in an entity is done by placing the person symbol in the entity symbol. (Since the person is inside the entity, the relationship is assumed and there is no need for a line linking the two.)



A person can be a member of more than one entity.



A person can be associated with an entity but not a member of that entity.



If Jones was associated directly with Smith and not just the Mongols, you could extend the line to Smith.



If Jones was known to be associated with the Mongols, and was believed to be associated with Smith you could display that like this:



As your chart grows you should avoid crossed association lines wherever possible.



Instead rearrange your chart elements. If there is no other way, display the lines like this:



You can depict past membership in an organization. If Smith is the current president of the Mongols, and Davis is the former president you could depict it like this. This would also work if Davis’ membership was suspected and not known.



Here’s what a completed Link Analysis chart looks like.



This chart was from an actual bank robbery conspiracy that I worked on. Any idea who the main actor was?

Methods To Create Charts
There are a number of methods you can use to create the various Link Analysis charts. Each of these methods has its strengths and weaknesses. They are:

  • Pencil and paper
  • Generalized computer drawing applications 
  • Specialized Link Analysis software

The first method, pencil and paper, has the advantage of having nearly no learning curve to operate. It’s also supremely portable and there is a very strong possibility that your organization already possesses them so the impact to your budget is minimal. The downside is that rearranging the elements on your chart is messy and time consuming. A drafting circle template or flowchart template can make your drawings much neater.

The second method is my favorite. Drawing programs can be found on most computers and range from limited functionality programs such as Paintbrush to full blown professional grade CAD or drawing programs. One that nearly every police agency possesses is Microsoft Office. MS Office’s tools have drawing tools and probably the easiest way to utilize them is by using PowerPoint. The line tool will also snap to points on the shapes and stay connected. This helps when rearranging objects on the page as the lines will stay connected to the shape while you rearrange your chart. Those same drawing tools are also available in Word though the commands to access them are a bit buried in Word’s UI.

The last method is using specialized link analysis software such as i2 or RFFlow. These applications are great in that they are specifically designed for link analysis however; they can be costly and have somewhat steep learning curve to get good results.

As was stated in the Introduction, “Don’t let the tools drive the problem”. The method you use is not as important as the chart you create. A messy but accurate pencil chart beats a neat, computer generated but inaccurate chart hands down.

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