How to Use the Scientific Method to Research Crime

As a criminal investigator, you should begin by making observations. At a robbery scene, you may notice a lipstick tube lying partially hidden in a corner. That could be a clue that leads you to make further observations and look for additional evidence -- data collection is step 2 in the process.

In hypothesis formulation -- the next step in the scientific process -- you make an educated guess about the crime based on data you've gathered. The more observations you made and data you collected in the first two steps, the better your hypothesis will be. Form a hypothesis you can test using deductive reasoning -- for example, "The theft occurred at night and the thief was a smoker who wore sneakers." You could use deductive reasoning to test the hypothesis if you had tangible evidence that supported those theories. Deductive reasoning, often used by Sherlock Holmes, is a thought process wherein you reach a conclusion based on information you already have. Your hypothesis should also list your evidence along with items detailing possible criminal motives and personality characteristics of the offender.

Armed with a hypothesis that paints a picture of the offender, review your evidence and reevaluate that picture as new evidence and information arrive. If certain aspects of your evidence leave you with questions, you should consult "appropriate forensic scientists," according to criminal profiler Brent E. Turvey in the book "Criminal Profiling: An Introduction to Behavioral Evidence Analysis."

At this point in the investigation -- just before you make a conclusion based on the hypothesis -- you should interpret your results. Do so by reviewing the offender characteristics you derived and eliminating those that your data and evidence do not support. Draw your conclusion by emulating Sherlock Holmes and writing a profile that describes the offender based on your evidence. Profile characteristics should include items such as the offender's personality, emotional state and psychological state. You may even be able to include gender-specific information if your evidence supports it.

Take your time forming a hypothesis and think logically and objectively -- like a scientist performing an experiment. As with any analysis that uses the scientific method, you may discover that your hypothesis is wrong. Ensure that your data is correct and formulate another hypothesis using what you've learned to create a better one. You can then repeat the scientific method steps and hopefully arrive at conclusion that helps you nab your suspect.