More Thoughts On Bias
Posted: Thu Feb 22, 2007 11:45 am
Recently I have been reading the book “Speaking as an Expert: A Guide for the Identification Sciences from the Laboratory to the Courtroom” by Stephen C. McKasson and Carol Richards, Charles C. Thomas Publisher, 1998, LCCCN: 97-32099. They have some interesting things to say about bias and the following is an excerpt from pp 9-10.
“For example, there are some examiners who say that they want to know as few details about a case as possible before starting the examination process to avoid bias. This is a very scary statement because it seems to say that a scientist cannot sort out the facts by observation if he or she is given outside information. It had better be the case that nothing could be further from the truth! What is bias but a negative word for a working hypothesis? A scientist works with bias constantly, but since he or she is trained to test and prove a position, an expert opinion; bias should not be a problem. A good scientist should not have to be unbiased, but rather, should be observant of those things that will either convert a bias into a well reasoned and well supported conclusion or expose the bias as wrong (Hively, 1996). “The better equipped he (or she) is to understand his (her) own biases and prejudices the better forensic scientist he (she) will be” (Turner in Davies, 1974, p.7).”
“It is possible that the examiner is more concerned with the appearance of bias to a judge or jury rather than with actual undue influence. Here again, we reject the argument because it is far more appropriate to demonstrate how bias is dealt with by the scientist, especially since it is impossible to avoid. Remember, a complete lack of bias would mean the inability to make assumptions, of any kind, and that would throw all scientific endeavors out of the realm of observation and into the world of guessing.”
“Our solution is a simple one. ……Know your discipline. Know its theory and its practice. Know its hypotheses and its assumptions. Know what you know. Observe well and that includes observing your observations.”
Both McKasson and Richards have more to say on the subject of bias and I believe it is certainly worth reading.
I have also recently been talking to persons who are involved in Photographic Analysis (Interpretation if you wish). Bias is also a concern in their discipline. This is countered by teaching the subject of bias in their training program. Also they do not have a system of verification as the latent print discipline does, but they do have peer review, which they call ‘presentation’. When conclusions or decisions are made they must present their reasoning and justification behind the conclusion to a team (3 or more). I do not mean just handing some people some photographs and saying this is my conclusion, look for yourself. They must present it: the good, the bad and the ugly. The pros and cons. They must account for what they observe, the conclusion and how they arrived at that conclusion.
From my POV “blind verification” is an approach to deal with “confirmation bias”. Is it the only approach to deal with confirmation bias? I do not believe so. I also believe that blind verification is not the best or even a reasonable approach to deal with “Bias”. My reasoning for that is:
1. BV is not used in other disciplines of scientific inquiry!
2. BV has not been tested sufficiently as a means for dealing with biases!
3. BV replaces “Peer Review” as means of checking conclusions!
4. BV will confuse those not in the discipline when small differences are noted that do not effect the overall conclusion.
5. BV will decrease operational efficiency.
6. BV will foster a system of second guessing instead of real scientific process of Peer Review.
7. BV will disable the learning process in how other examiners reach conclusions.
So if I reject Blind Verification as the only means of overcoming biases or if I reject it as the “best” means of overcoming biases, then I must have something to fall into its place.
The first step is to increase awareness. If you do not have a section on “Biases” in your training manual, put it in there. If you already have training block on what is Biases and dealing with them, then strengthen it.
The second step is those single latent prints with poor quality and reliability or from high profile cases these should be “Presented”. I do not mean just verify but the Examiner (Analyst) must present to a group. They must be able to point out each distortion effect. Each ridge feature. Each feature relationship. They must be able to discuss the Substrate or Matrix when necessary. They must be able to present each factor that was related to their conclusion. I would bet that if someone made a presentation on a particular latent print that all features were clear and sharp and any discrepancies could be accounted for by a 66 degree twist, some eyebrows would have been raised. Each presentation must follow an outline on all aspects of a latent print analysis. If a particular aspect does not apply then they must say so. Will this work with smaller agencies that only have 1-4 examiners. It would if there was an agreement between some agencies. It would be like Ms Saviers said in an earlier post. It probably is better.
They say if you want to learn something very well, then teach it. If LPE’s have to present their conclusions on difficult latent prints it will improve their communication skills and their craft far better than two examiners doing it blind and writing it on a sheet of paper. Full Presentation is a high form of “Peer Review”.
Your comments are welcome.
“For example, there are some examiners who say that they want to know as few details about a case as possible before starting the examination process to avoid bias. This is a very scary statement because it seems to say that a scientist cannot sort out the facts by observation if he or she is given outside information. It had better be the case that nothing could be further from the truth! What is bias but a negative word for a working hypothesis? A scientist works with bias constantly, but since he or she is trained to test and prove a position, an expert opinion; bias should not be a problem. A good scientist should not have to be unbiased, but rather, should be observant of those things that will either convert a bias into a well reasoned and well supported conclusion or expose the bias as wrong (Hively, 1996). “The better equipped he (or she) is to understand his (her) own biases and prejudices the better forensic scientist he (she) will be” (Turner in Davies, 1974, p.7).”
“It is possible that the examiner is more concerned with the appearance of bias to a judge or jury rather than with actual undue influence. Here again, we reject the argument because it is far more appropriate to demonstrate how bias is dealt with by the scientist, especially since it is impossible to avoid. Remember, a complete lack of bias would mean the inability to make assumptions, of any kind, and that would throw all scientific endeavors out of the realm of observation and into the world of guessing.”
“Our solution is a simple one. ……Know your discipline. Know its theory and its practice. Know its hypotheses and its assumptions. Know what you know. Observe well and that includes observing your observations.”
Both McKasson and Richards have more to say on the subject of bias and I believe it is certainly worth reading.
I have also recently been talking to persons who are involved in Photographic Analysis (Interpretation if you wish). Bias is also a concern in their discipline. This is countered by teaching the subject of bias in their training program. Also they do not have a system of verification as the latent print discipline does, but they do have peer review, which they call ‘presentation’. When conclusions or decisions are made they must present their reasoning and justification behind the conclusion to a team (3 or more). I do not mean just handing some people some photographs and saying this is my conclusion, look for yourself. They must present it: the good, the bad and the ugly. The pros and cons. They must account for what they observe, the conclusion and how they arrived at that conclusion.
From my POV “blind verification” is an approach to deal with “confirmation bias”. Is it the only approach to deal with confirmation bias? I do not believe so. I also believe that blind verification is not the best or even a reasonable approach to deal with “Bias”. My reasoning for that is:
1. BV is not used in other disciplines of scientific inquiry!
2. BV has not been tested sufficiently as a means for dealing with biases!
3. BV replaces “Peer Review” as means of checking conclusions!
4. BV will confuse those not in the discipline when small differences are noted that do not effect the overall conclusion.
5. BV will decrease operational efficiency.
6. BV will foster a system of second guessing instead of real scientific process of Peer Review.
7. BV will disable the learning process in how other examiners reach conclusions.
So if I reject Blind Verification as the only means of overcoming biases or if I reject it as the “best” means of overcoming biases, then I must have something to fall into its place.
The first step is to increase awareness. If you do not have a section on “Biases” in your training manual, put it in there. If you already have training block on what is Biases and dealing with them, then strengthen it.
The second step is those single latent prints with poor quality and reliability or from high profile cases these should be “Presented”. I do not mean just verify but the Examiner (Analyst) must present to a group. They must be able to point out each distortion effect. Each ridge feature. Each feature relationship. They must be able to discuss the Substrate or Matrix when necessary. They must be able to present each factor that was related to their conclusion. I would bet that if someone made a presentation on a particular latent print that all features were clear and sharp and any discrepancies could be accounted for by a 66 degree twist, some eyebrows would have been raised. Each presentation must follow an outline on all aspects of a latent print analysis. If a particular aspect does not apply then they must say so. Will this work with smaller agencies that only have 1-4 examiners. It would if there was an agreement between some agencies. It would be like Ms Saviers said in an earlier post. It probably is better.
They say if you want to learn something very well, then teach it. If LPE’s have to present their conclusions on difficult latent prints it will improve their communication skills and their craft far better than two examiners doing it blind and writing it on a sheet of paper. Full Presentation is a high form of “Peer Review”.
Your comments are welcome.