Where reliability will be determined by the judge, what I see is the person using the phrase, “To a reasonable degree of scientific certainty”, to be challenged more as to the meaning of the statement. If the person cannot explain why he or she is right to use the phrase as compared to a large portion of the forensic scientific community. It is a gamble that each individual need decide on their own as to whether or not to take it. If they’re successful, then the testimony may hold more weight, however, if they are not successful, it could cause less weight.

As I have previously said, at this time and date an expert in most cases will not be allowed or may not be allowed to testify if they cannot give some degree of certainty to their opinion. The question is, how do they express this degree of certainty. I do not think the word scientific even needs to come into the equation when giving a degree of certainty. One can use the words, “A preponderance of the evidence, clear and convincing, or more likely than not, as a method of describing the degree of certainty. In most civil cases, all that is asked for is a preponderance of the evidence I do understand that in criminal cases the level of certainty may need to be greater and here's where the term clear and convincing may be sufficient. By using these terms when it’s not giving a numerical percentage as to the certainty. Where, if one says a degree of certainty, then the question can be asked as to what the numerical amount of that degree is. When the word "degree” is used in the context of the phrase “degree of scientific certainty” it suggests there is a numerical amount attached to the word degree. One of the definitions of degree is the amount, level, or event to which something happens or is present.

Each individual needs to make the decision on their own. They and only they will be required to give a reason for the decision is made. The other thing is that in each case, the perception of the degree of certainty may be different as to what is required by the judge for him to allow the person to testify. And one of my other postings I gave example where a person with saying he had a 95% degree of certainty that his opinion was correct, was not allowed to testify, all I’m saying is to be careful.

I agree there is no quantitative measure of the level of certainty but is saying that the word degree has been removed. The terms, preponderance of the evidence, clear and convincing, or more likely than not are quantitative terms. What does the average person associate with the word degree? Remember, you will not be sparking to a person involved in the forensic science profession. You need to speak in terms that the audience will understand. Most individuals hear the word degree used in describing temperature. It is a numerical number they are associating with the word. That is what they will be expecting to hear from the investigator.

Both the Daubert and Frye tests, when properly implemented, serve to screen out speculative testimony and thus further demonstrate the lack of need for the "reasonable degree of certainty" language. Neither require a level of certainty.

Based on several articles it appears that most in the legal profession agree that an expert’s opinions must be reasonably certain to be admissible, and that the phrase lacks a consistent definition. A gap exists in the literature regarding the definition and importance of the phrase reasonable degree of certainty, resulting in broad variations in the way the phrase is interpreted and used in the legal profession. This is what is creating confusion in the forensic science profession.

You have every right to believe in your position. As I have said, it is not always the majority that is right on a specific opinion. All I am saying is that in using the phrase one needs to be able to explain why they believe they are correct and how that phrase has a reasonable meaning. I disagree that this is the only method for the judge to decide that you are a professional and have properly applied the scientific method.

Jim Mazerat
Forensic Investigations Group