The reliable use of such information is steeped in the context of evidence. The SM requires evidence to formulate (as opposed to "consider") a valid hypothesis. Also for scientific reliability, evidence is required to disprove a valid hypothesis.

So what is evidence? Let's first start with information. Data can be defined as information that is documented and verifiable. Evidence can be defined as data that is both relevant and reliable in a specific context. A good example is data that there is a "for sale" sign on the front lawn of the house during a fire. A valid hypothesis would be that the house was "for sale" at the time of the fire. Further evidence could be used to test this valid hypothesis to try and disprove the valid hypohtesis. Was the home not "for sale" and the sign had not been removed (disproved). Or was the house "for sale" (consistent with the hypothesis)?
The presence of a "for sale" sign is not relevant and reliable to be used as evidence that the intent was an incendiary fire.

When applying the SM in a scientifically reliable manner, the investigator needs to determine what is evidence and what is not evidence in a specific context. In addition, the investigator needs to understand when to use specific evidence in a reliable manner. Using evidence of motive, means, and opportunity before reliably determining an incendiary fire is not a reliable methodology.

Douglas J. Carpenter, MScFPE, CFEI, PE, FSFPE
Vice President & Principal Engineer
Combustion Science & Engineering, Inc.
8940 Old Annapolis Road, Suite L
Columbia, MD 21045
(410) 884-3266
(410) 884-3267 (fax)
www.csefire.com