We know that when being qualified to testify one area of questioning you can almost be sure to encounter is what your methodology was when you conducted the investigation. When it comes to fire investigations we have been taught the seven steps that are found in NFPA 921. I heard a person testify that he followed the scientific method when conducting the investigation. He said while NFPA 921 has seven steps his investigation was based on five steps. His five steps were ones contained within the seven steps found in 921. The opposing attorney challenged the expert on the fact that if he left out the first two steps of the scientific method what else did he fail to do. What turned out to be interesting was the fact that the judge had a degree in chemistry. The judge stated that he had been taught that the scientific method consisted of making observations, formulating hypotheses, and designing experiments, which in turn lead to additional observations, hypotheses, and experiments in repeated cycles until one reaches the point that there is only one hypothesis that could not be proven wrong. Remember this was a hearing on a motion so the judge got to not only ask the witness questions but also the attorneys. The judge went on to question the expert and then stated where NFPA 921 has seven recommended steps, it is not necessary for all the steps to be addressed by the witness. What the judge was looking for was the core of the methodology. He said the expert made observation during the data collection process. The judge believed that the analysis process and developing an hypothesis was one in the same. He did ask the expert if he developed more than one hypothesis and the expert said he did. The expert went through the process of each hypothesis that was tested and the results of those findings. He then explained that with the available data there was one that could not be disproved. This satisfied the judge and the expert was allowed to testify.

He we had an expert that was comfortable and knowledgeable and could properly express this methodology. Where his methodology was not exact to what was found in 921, his explanation was sufficient for the judge.

The question is, as it was in this case, is there more than one explanation of the scientific method that is acceptable for fire investigation or does the investigator need to strickly follow what is found in 921?

Jim Mazerat
Forensic Investigations Group