Archive for May, 2012

by: Jason A. Sutula

I strongly recommend reading the book “The Demon-Haunted World: Science as a Candle in the Dark” by Carl Sagan to anyone serious about utilizing the Scientific Method in fire investigation. Sagan always was a gifted writer who had the ability to take very complex ideas and break them down into manageable and much more easily understood segments. “The Demon-Haunted World” is no exception to the rule. In this book, Sagan presents the Scientific Method in a fashion that is easy to grasp. Additionally, he provides several practical tools that can be carried throughout our professional (and personal) lives to think more critically and skeptically about the world around us. These tools should and can be routinely used in the realm of Fire Investigation.

From a reference more familiar to many of us in the field of Fire Investigation, NFPA 921 – Guide for Fire & Explosion Investigations provides a very clearly defined section on what the Scientific Method is and how it is used during a fire investigation. In general, NFPA 921 requires that a systematic approach is used to come to a determination of both the origin and cause of a fire. The systematic approach that is recommended is the Scientific Method.

Various forms and flow charts of the Scientific Method exist in greater and lesser detail. The basic concepts of the Scientific Method do not change though, no matter how the “blueprint” is presented. The Scientific Method always starts by recognizing that a need exists (i.e., a fire has occurred and we need to figure out where and how it started, if possible). Once we have recognized and identified our problem, the problem must be specifically defined. Thus, if we want to focus on determining the origin of the fire (which should always be determined BEFORE the cause), we must decide that this is our problem. Next, we must collect all of the available data in the case. An example list of what this data is and where it comes from could potentially encompass an entire post all by itself, but a few examples are eye-witness statements, surveillance video, fire service personnel statements, fire department reports, police reports, etc. After we have exhausted all avenues of potential data, the data must then be analyzed. Hopefully, the data is sufficient to develop a set of possible hypotheses that can account for the resulting data. Once these hypotheses (or a lone hypothesis in rare cases) are developed, they must be tested. Testing can range from very complex to very simple. Comparing the developed hypotheses against the fire department report or pieces of physical evidence found at the scene may be enough to decide that certain hypotheses are just not possible. The Scientific Method must be thought of as an iterative process, though, where each hypothesis is tested until it is verified, ruled out, or a determination is made that there is insufficient data to verify it or rule it out.

Using the Scientific Method while performing fire investigation has taken on even more importance in the last decade. This is due in part to a much more fundamental and better understanding of fire phenomenon and fire dynamics as well as several landmark rulings in the court system. In particular, Daubert v. Merrel Dow Pharmaceuticals has established that the court is the “gatekeeper” in determining whether or not an expert in the field has used proper methodology when arriving at his/her conclusion. While this new precedent specifically affects cases tried under federal rules, a fire investigator would be prudent to conduct their investigations using the Scientific Method with the belief that their methodology could be under scrutiny based on Daubert.

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