"If I am understanding what you are saying is that data’s relationship to evidence is based on the context of the purpose it is being viewed. There is a transition period between data and when it becomes evidence. I tend to look at the alarm as evidence from the beginning because I would say all my investigations revolve around more than the origin and cause. The investigation into the question was there an alarm present and did it activate may or may not have anything to do with the origin and cause. The occasion may develop where it becomes evidence in the origin and cause investigation. Basically, I am running parallel investigations which may or may not combine at appoint in time. That is why I consider most data as evidence. This is true with not only an alarm but maybe with the building construction."

The path for data to become evidence is through an analysis of its relevance and reliability as evidence in a specific context using the SM. Yes, there can be a delayed in such an assessment based on timing and the iterative process of the application of the SM.

"What you are saying is that all data must be considered. As the investigation proceeds that date may or may not evolve into evidence that can be used in the evaluation of one or more hypotheses."

"I think the terminology being used, “invalid” and “unsupported” relates to the person’s education in the use of these terms. In the dictionary the word invalid is defined as being without foundation or force in fact, truth, or law. The example they give is “an invalid assumption”. Unsupported is defined as being not verified or unsubstantiated. I must agree of the two, unsupported better relates to what we are trying to say. Very good point."

In 921, a "valid hypothesis" is a hypothesis that was FORMULATED with evidence using deductive reasoning. Accordingly, an "invalid hypothesis" is one that FORMULATED without evidence. One can CONSIDER hypotheses using the ANALYZE THE DATA step of the SM in 921. One is using his/her education, knowledge, skill, and experience to consider what could have happened, as opposed to what most reliably did happen. In the end, the SM does not care about what could have happened, but what reliably did happen. This concept is not based on a person's education, but is based on a specific definition used in 921.There is a significant difference between CONSIDERING hypotheses and FORMULATING hypotheses.An Invalid Hypothesis is one that is unsupported with evidence and thus, subjective.

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