DC Sniper Case: Example Hypothesis and Evidence Development
Submissions Instructions: Expand upon (add to or change) the example hypotheses and evidence. Post your analysis to the Lesson 5 Discussion Forum.
Purpose: To complete the ACH steps of hypothesis generation and evidence development.
General. Analysis of Competing Hypotheses, ACH, is a simple model for how to think about and fuse geospatial information into analytic problems. As we have included ACH in our geospatial analytic method, it takes the geospatial analyst through a process to make well-reasoned, analytical judgments using both non-geospatial and geospatial information. It is particularly useful for predictions of what is likely to happen in the future. It helps an analyst to minimize some of the cognitive limitations we discussed earlier. The key elements of ACH we are going to address in this exercise are:
- Identify the possible hypotheses to be considered. Use a group of analysts with different perspectives to brainstorm the possibilities.
- Make a list of evidence and arguments for and against each hypothesis.
According to Heuer, a hypothesis is a testable proposition about what is true, or about what has happened, is happening, or will happen. It should usually be worded as a positive statement that can be disproved. The most effective hypotheses meet two tests. (1) The hypotheses are mutually exclusive. That means if one hypothesis is true, then all other hypotheses must be false - in other words, no overlap between hypotheses. (2) The hypotheses cover all reasonable possibilities, including those that seem unlikely but not impossible. As evidence is collected and added to the matrix, you may find that hypotheses need to be reworded, added, deleted, or combined.
Again, according to Heuer, when identifying relevant evidence, consider each hypothesis, one at a time, and ask yourself: What evidence would I expect to see if this hypothesis is true? Also, what evidence would I expect not to see if this hypothesis is true? You will generally find that each hypothesis leads you to seek out somewhat different evidence. Evaluation of all reasonable hypotheses may require that you explore hypotheses you have not seriously considered before. To appreciate the geospatial aspects of the problem, it will be necessary to map the data!
What to do: Expand upon (add, delete, or modify information) the following hypothesis and evidence lists developed from the DC Sniper Case study:
- Initial hypotheses:
- Disgruntled Michael's employee
- Foreign terrorist
- Serial killer
- Domestic terrorist
- Initial evidence:
- Conforms to the geospatial model of a serial criminal.
- The majority of the shootings were at or near shopping centers. That is, the events are not near governmental buildings indicating that government is not a target.
- Shootings were all on major highways or interstates for a quick exit from the scene. This indicates a desire not to be caught.
- There was only one shooting per location and often occurred at gas stations. This seems to indicate our Sniper is not in the role of a suicide terrorist.
- Sighting of a blue car with two black men.
- Sighting of a white van with two individuals at one killing.
- Military caliber weapon (5.56mm). This caliber is common to the US military and is also a sporting cartridge.
- Noise heard but shooter never seen. This possibly indicates some sniper training.