Friction Ridge Process Map
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Bill Schade
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Friction Ridge Process Map
First Impression
I didn't think it was possible to make the Human Factors Group Flowchart any more complicated. I guess I was wrong
Bill Schade
I didn't think it was possible to make the Human Factors Group Flowchart any more complicated. I guess I was wrong
Bill Schade
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Dr. Borracho
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Re: Friction Ridge Process Map
Kind of like, if you took the Mona Lisa and cut it up into pizza slices, then found somebody who had never seen the painting and showed them the sections one at a time and expected them to envision and appreciate the painting as a whole.
"The times, they are a changin' "
-- Bob Dylan, 1964
-- Bob Dylan, 1964
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josher89
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Re: Friction Ridge Process Map
Keep in mind this is NOT the OSAC-supported process map; this is a conglomeration of all possible ACEV processes CURRENTLY being utilized. It is a snapshot of the current way things are being done (not by every shop and not at every level of the map).
It's merely there to show how things are being done currently.
But you are right, who ever though the Human Factors map was confusing didn't hear the "Here, hold my beer..."
It's merely there to show how things are being done currently.
But you are right, who ever though the Human Factors map was confusing didn't hear the "Here, hold my beer..."
"...he wrapped himself in quotations—as a beggar would enfold himself in the purple of emperors." - R. Kipling, 1893
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NRivera
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Re: Friction Ridge Process Map
It has also been expanded so the task groups can use it in crafting new documents. It makes it easier to drill down on key decision points in the process.
"If at first you don't succeed, skydiving was not for you."
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Steve Everist
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Re: Friction Ridge Process Map
My first question upon seeing this 13-page document is, "What is the purpose of this???" So I read the Introduction to the Friction Ridge Process Map on the first page, which ends with:josher89 wrote: ↑Thu Dec 12, 2019 9:27 am Keep in mind this is NOT the OSAC-supported process map; this is a conglomeration of all possible ACEV processes CURRENTLY being utilized. It is a snapshot of the current way things are being done (not by every shop and not at every level of the map).
It's merely there to show how things are being done currently.
But you are right, who ever though the Human Factors map was confusing didn't hear the "Here, hold my beer..."
I'm not sure how discussions are going in other labs, but if most of it revolves around, "What... we don't do that - who does that?" Then the intended purpose may not be realized. Taking an amalgamation of processes that may or may not be in use in many (or any) labs, and then representing them all together just becomes confusing.The intended uses of this process map are to facilitate discussions about key decision points in the ACE‐V process, help the research and standard’s development community be able to cite the specific latent print activity that their efforts address, and enable laboratory managers to better understand how their protocols compare with other laboratories.
There are references to outdated documents from SWGFAST and drafts of documents that were never finalized, and thus may not be currently used. There's reference to the OSAC Standard for Friction Ridge Examination Conclusions, Draft which I haven't heard of any agencies routinely using this system of reporting conclusions. It's been proposed, presented, and discussed - but do any of the current people putting this draft forward currently use this system in their reporting and in their SOPs?
And maybe the best way that we can "enable laboratory managers to better understand how their protocols compare with other laboratories," is those lab managers should be in contact with one-another to find this out. I think the sharing of this information, SOPs, quality manuals, training manuals, etc... between agencies of similar sizes and resources is much more effective than throwing out a visual "process stew" and trying to take a bite of that.
I'm just afraid that the intent of the map is lost (especially by those who don't read the bottom of page 1), and I'm not sure that it will effectively be achieved.
Steve E.
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Shane Turnidge
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Re: Friction Ridge Process Map
If this doesn't make you appreciate the intuitiveness of competent examiners I don't know what would.
FWIW I actually appreciate that someone (group) is trying to drill down on the various processes in the friction ridge analysis world. The process should become standard at some point, but here we are at the end of 2019, and in many jurisdictions it is still 1985.
Shane Turnidge
FWIW I actually appreciate that someone (group) is trying to drill down on the various processes in the friction ridge analysis world. The process should become standard at some point, but here we are at the end of 2019, and in many jurisdictions it is still 1985.
Shane Turnidge
You're only as good as your last Ident.
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g.
- Posts: 247
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- Location: St. Paul, MN
Re: Friction Ridge Process Map
Steve,There's reference to the OSAC Standard for Friction Ridge Examination Conclusions, Draft which I haven't heard of any agencies routinely using this system of reporting conclusions. It's been proposed, presented, and discussed - but do any of the current people putting this draft forward currently use this system in their reporting and in their SOPs?
I have been using the OSAC standard for conclusions for 6 months or so now. I have presented it in court/to jurors/judges. I know of at least 4 agencies that currently are proposing to adopt the standard, but I don't think have done so yet.
I get positive feedback regarding the standard, but I find it is in the delivery and showing how it can be used, including what conflict resolution looks like and it's not that difficult to employ.
I have heard a good deal of negative reaction to it as well, but I have heard no good arguments. Only fear, misunderstanding, a lack of wanting anything more than value/no value for ID and an adherence to "simple" reporting (ID or Exclusions).
Incidentally, now that I am using a stats model for fingerprints too, it makes using the OSAC conclusion model even easier.
g.
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Michele
- Posts: 384
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Re: 5 conclusions
Glenn,
My reasons for not using it are listed below. I’ve asked these questions to those on the OSAC but have never gotten answers other than ‘hard work has gone into this so we should respect the work that’s been done’. To me, that’s not an answer, that’s asking for it to be rubber stamped.
1) I wonder what the purpose is. If I knew the purpose I could judge if the purpose is being achieved. Is it to gain consistency? ID, INC, and EX are consistent verbiage but not used consistently – the parameters of the 5 proposed conclusions are not listed so do we know that these will be used more consistently?
2) These conclusions are proposed without instructions (i.e. no methodology document), how can they be used appropriately without instructions? I’ve been told that it’s up to agencies to decide how to use the conclusions. I don’t see that as being helpful or making things more consistent.
3) Without instructions, are the extra 2 conclusions dividing up inconclusive conclusions into more categories or dividing up ID’s into more categories? I’ve heard different thoughts from different people which seems to show that instructions are necessary (if the intent is to be more specific).
4) Have these 5 conclusions been tested to see if other conclusions would be valuable (should there be 6 or 7 or 8 conclusions)?
5) Have these 5 conclusions been tested to see if they are more transparent? Those proposing them have said they are not using them. If these conclusions are more valuable, why aren’t they using them? I would think they would feel ethically compelled to use the best conclusions whether approved or not.
6) Would these 5 conclusions protect against errors? How would the examiners in the Mayfield case have reported under this proposal? Wouldn’t they still have reported ‘Source ID’ meaning “Source Identification is reached when the friction ridge impressions have corresponding ridge detail and the examiner would not expect to see the same arrangement of details repeated in an impression that came from a different source.” (quoted from the OSAC document)
As you know from your research, we do not expect to see a lot of things but that doesn’t mean they don’t exist (the high erroneous exclusion rate for example).
7) The OSAC members on the ASB have explained to the ASB that Source ID is not the same as the historic meaning of ID. Is that nuance apparent? In your use of it, are you using the new term ‘Source ID’?
8) You mentioned these conclusions are easier to use with a statistical model. Which model are you using? Does it consider things like the number of intervening ridges, creases or discrepancies? Does the model you’re using work on palm prints or foot prints? If an agency is not using a model, does that mean the 5 proposed conclusions are not as easy to use?
9) If ‘Support for Same Source’ ranges from limited to moderate to strong support, isn’t that 3 different situations? Why not make those different conclusions to be more transparent? And how is the difference between limited, moderate, strong, and extremely strong support determined? Where would the Mayfield comparison be placed?
10) What is Support for Different Sources? If I can’t find consistency, is that ‘Support for different sources? Just because I can’t find my car keys in my house doesn’t mean there is support that they aren’t there. If practitioners report out ‘support for different sources’ in this situation, it seems very misleading.
These are not all of my questions but if they were answered it would certainly be a start on understanding the document (and then it would be possible for me to consider using it).
I think the misunderstandings that you’ve heard stem from the document being so vague that it’s difficult, if not impossible, to understand. I certainly am not in the group that wants conclusions to be simple. I agree the disciple could benefit from a wider range of conclusions; I just don’t see these conclusions as being beneficial. I think they create more confusion than clarification.
You mention that you haven’t heard any good arguments against the 5 conclusions. I don’t have any arguments, just lots of questions that haven’t been answered (and believe me, I keep asking hoping that someone will be able to give a good answer).
My reasons for not using it are listed below. I’ve asked these questions to those on the OSAC but have never gotten answers other than ‘hard work has gone into this so we should respect the work that’s been done’. To me, that’s not an answer, that’s asking for it to be rubber stamped.
1) I wonder what the purpose is. If I knew the purpose I could judge if the purpose is being achieved. Is it to gain consistency? ID, INC, and EX are consistent verbiage but not used consistently – the parameters of the 5 proposed conclusions are not listed so do we know that these will be used more consistently?
2) These conclusions are proposed without instructions (i.e. no methodology document), how can they be used appropriately without instructions? I’ve been told that it’s up to agencies to decide how to use the conclusions. I don’t see that as being helpful or making things more consistent.
3) Without instructions, are the extra 2 conclusions dividing up inconclusive conclusions into more categories or dividing up ID’s into more categories? I’ve heard different thoughts from different people which seems to show that instructions are necessary (if the intent is to be more specific).
4) Have these 5 conclusions been tested to see if other conclusions would be valuable (should there be 6 or 7 or 8 conclusions)?
5) Have these 5 conclusions been tested to see if they are more transparent? Those proposing them have said they are not using them. If these conclusions are more valuable, why aren’t they using them? I would think they would feel ethically compelled to use the best conclusions whether approved or not.
6) Would these 5 conclusions protect against errors? How would the examiners in the Mayfield case have reported under this proposal? Wouldn’t they still have reported ‘Source ID’ meaning “Source Identification is reached when the friction ridge impressions have corresponding ridge detail and the examiner would not expect to see the same arrangement of details repeated in an impression that came from a different source.” (quoted from the OSAC document)
As you know from your research, we do not expect to see a lot of things but that doesn’t mean they don’t exist (the high erroneous exclusion rate for example).
7) The OSAC members on the ASB have explained to the ASB that Source ID is not the same as the historic meaning of ID. Is that nuance apparent? In your use of it, are you using the new term ‘Source ID’?
8) You mentioned these conclusions are easier to use with a statistical model. Which model are you using? Does it consider things like the number of intervening ridges, creases or discrepancies? Does the model you’re using work on palm prints or foot prints? If an agency is not using a model, does that mean the 5 proposed conclusions are not as easy to use?
9) If ‘Support for Same Source’ ranges from limited to moderate to strong support, isn’t that 3 different situations? Why not make those different conclusions to be more transparent? And how is the difference between limited, moderate, strong, and extremely strong support determined? Where would the Mayfield comparison be placed?
10) What is Support for Different Sources? If I can’t find consistency, is that ‘Support for different sources? Just because I can’t find my car keys in my house doesn’t mean there is support that they aren’t there. If practitioners report out ‘support for different sources’ in this situation, it seems very misleading.
These are not all of my questions but if they were answered it would certainly be a start on understanding the document (and then it would be possible for me to consider using it).
I think the misunderstandings that you’ve heard stem from the document being so vague that it’s difficult, if not impossible, to understand. I certainly am not in the group that wants conclusions to be simple. I agree the disciple could benefit from a wider range of conclusions; I just don’t see these conclusions as being beneficial. I think they create more confusion than clarification.
You mention that you haven’t heard any good arguments against the 5 conclusions. I don’t have any arguments, just lots of questions that haven’t been answered (and believe me, I keep asking hoping that someone will be able to give a good answer).
Michele
The best way to escape from a problem is to solve it. Alan Saporta
There is nothing so useless as doing efficiently that which should not be done at all. Peter Drucker
(Applies to a full A prior to C and blind verification)
The best way to escape from a problem is to solve it. Alan Saporta
There is nothing so useless as doing efficiently that which should not be done at all. Peter Drucker
(Applies to a full A prior to C and blind verification)
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Boyd Baumgartner
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Dr. Borracho
- Posts: 157
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Re: Friction Ridge Process Map
Exactly!Boyd Baumgartner wrote: ↑Fri Dec 20, 2019 8:40 pmHere's one. They haven't been studied as to whether or not they are valid or reliable in performance testing.
If the argument being used against traditional latent print examination and conclusions is that in over a century of use, we have not scientifically validated our processes to assure accuracy or reliability, then I would submit that the critics are guilty of the same offense to an even greater degree in pushing the profession too rapidly down a different path.
Is the pot calling the kettle black? Which is which?
"The times, they are a changin' "
-- Bob Dylan, 1964
-- Bob Dylan, 1964
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Boyd Baumgartner
- Posts: 567
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Re: Friction Ridge Process Map
I always laugh at the overwrought complications that our discipline self inflicts when there's literally exact methods from which to borrow.
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g.
- Posts: 247
- Joined: Wed Jul 06, 2005 1:27 pm
- Location: St. Paul, MN
Re: Friction Ridge Process Map
These responses are for those sitting on the fence wondering if there is value to moving to a different system. I have no illusions that anything I say will convince anyone here to change your mind. If you find the clarifications helpful, then it was worth it. I will continue to use these conclusions; it has been very helpful for me and the examiners that I work with.
I am responding to the questions below. But it can all be summed up as the following : The OSAC standards allow more ways/options to communicate the weight of the evidence that you the expert have interpreted. They are more transparent and allow for subtler differences in support *IF your agency chooses to use all the options. You can just use the 5 broad options too.
"Support for same source" parameters are right in the definition. It's ANYTHING higher than inconclusive but not enough to ID. Now within THAT BROAD category of support for same source, you can parse out the weight to "limited", "moderate" "strong", if you wish, but that's not required.
An agency that has features in agreement, but insufficient to ID can say "Support for Same Source". An agency that has features in agreement (really close to an ID) could say "(Strong) Support for Same Source".
My recommendation is to include in your report a scale that shows INC<LIMITED<MODERATE<STRONG<EXTREMELY STRONG (SOURCE ID). I have a graphic that I use.
I would not expect them to be used "more consistently", given that our current conclusions vary in complex cases.
But that is a different argument than their value: which is to better capture the WEIGHT OF THE EVIDENCE as seen by the examiner. Two examiners may see the weight of evidence differently, but now they have more options to express that weight than a single gigantic broad inconclusive category which says nothing of the weight of the evidence.
The support for same source or support for different source categories would replace how many agencies currently use “inconclusive with features in agreement but not enough to ID” or “inconclusive with features in disagreement but not enough to exclude”.
Austin Hicklin addressed this at IAI. How can we test it effectively if we don’t make a change? Or if we test it significantly up front, what validity does it have if people have no reference point not having used the conclusions before. Agencies could do internal testing before adopting it; it would not need to be significant.
By definition, they are more transparent because by definition they allow the user to communicate a weight of evidence. The current conclusions do not communicate a weight of evidence.
How do YOU decide any categorical decision? You evaluate the weight of evidence and determine which category best describes the evidence as YOU have interpreted it, and have supporting data to back up that decision.
I use it in class all the time and students have no problem instantly adjusting and communicating. It’s about increased communication tools.
I’ve used both systems and now testified to both. First hand experience, the OSAC scale is a more transparent, and easier way to communicate, especially marginal, more difficult latent prints.
Your example is conflating two things. Your personal confidence in where to look for correspondence versus the possibility that you are missing the correspondence. If you don’t know where to look or lack complete exemplars then this would be in more of an INCONCLUSIVE situation. (or I prefer Alice White’s “Incomplete” for needing additional exemplars). But if you know where to look and have looked in those areas and have missed the correspondence and report “support for different source” then you are reporting the evidence and you interpreted it. You mis-interpreted it, but it’s as you interpreted it.
Eric and I did a podcast on these conclusions. We both had the same example of Support for Different Source: You find no corresponding features, all signs point towards an exclusion, but your agency REQUIRES, by policy, that you have a core/delta in your latent print to make an EXCLUSION decision.
[And I admit Boyd has a point. There are methods that exist to validate "conclusion scales". That would be an ideal approach. Given that the conclusions we currently use didn't go through ANY such process and given that we used them for decades BEFORE research emerged to performance test examiners.... I'm not too worried about making a lateral shift.]
g.
I am responding to the questions below. But it can all be summed up as the following : The OSAC standards allow more ways/options to communicate the weight of the evidence that you the expert have interpreted. They are more transparent and allow for subtler differences in support *IF your agency chooses to use all the options. You can just use the 5 broad options too.
The purpose is to better articulate the weight of the evidence and the degree of support for one proposition over the other.1) I wonder what the purpose is. If I knew the purpose I could judge if the purpose is being achieved. Is it to gain consistency? ID, INC, and EX are consistent verbiage but not used consistently – the parameters of the 5 proposed conclusions are not listed so do we know that these will be used more consistently?
"Support for same source" parameters are right in the definition. It's ANYTHING higher than inconclusive but not enough to ID. Now within THAT BROAD category of support for same source, you can parse out the weight to "limited", "moderate" "strong", if you wish, but that's not required.
An agency that has features in agreement, but insufficient to ID can say "Support for Same Source". An agency that has features in agreement (really close to an ID) could say "(Strong) Support for Same Source".
My recommendation is to include in your report a scale that shows INC<LIMITED<MODERATE<STRONG<EXTREMELY STRONG (SOURCE ID). I have a graphic that I use.
I would not expect them to be used "more consistently", given that our current conclusions vary in complex cases.
But that is a different argument than their value: which is to better capture the WEIGHT OF THE EVIDENCE as seen by the examiner. Two examiners may see the weight of evidence differently, but now they have more options to express that weight than a single gigantic broad inconclusive category which says nothing of the weight of the evidence.
There is a methodology document. That should not prevent ASB from approving a document that contains definitions about the conclusions.2) These conclusions are proposed without instructions (i.e. no methodology document), how can they be used appropriately without instructions? I’ve been told that it’s up to agencies to decide how to use the conclusions. I don’t see that as being helpful or making things more consistent.
Inconclusive would now only mean a zero balance towards either proposition of same/different source. It means the evidence either does not support either proposition (or equally negates each other).3) Without instructions, are the extra 2 conclusions dividing up inconclusive conclusions into more categories or dividing up ID’s into more categories? I’ve heard different thoughts from different people which seems to show that instructions are necessary (if the intent is to be more specific).
The support for same source or support for different source categories would replace how many agencies currently use “inconclusive with features in agreement but not enough to ID” or “inconclusive with features in disagreement but not enough to exclude”.
Not within fingerprints. Verbal scales such as these, to varying degrees, have been used in questioned documents for ages, footwear, trace evidence, facial, basically EVERY forensic discipline except fingerprints. Verbal scales of limited, moderate, strong, extremely strong have been used in Europe in some agencies for 30 years. They have been in use in France, Holland, England, Switzerland for fingerprints. Possibly others that I’m unaware of.4) Have these 5 conclusions been tested to see if other conclusions would be valuable (should there be 6 or 7 or 8 conclusions)?
Austin Hicklin addressed this at IAI. How can we test it effectively if we don’t make a change? Or if we test it significantly up front, what validity does it have if people have no reference point not having used the conclusions before. Agencies could do internal testing before adopting it; it would not need to be significant.
I can’t speak to why agencies have not adopted them. Perhaps they were waiting for ASB to approve them so they could move forward. Seeing that is not going to happen, I hope agencies begin adopting them without the sanction of ASB.5) Have these 5 conclusions been tested to see if they are more transparent? Those proposing them have said they are not using them. If these conclusions are more valuable, why aren’t they using them? I would think they would feel ethically compelled to use the best conclusions whether approved or not.
By definition, they are more transparent because by definition they allow the user to communicate a weight of evidence. The current conclusions do not communicate a weight of evidence.
Conclusions don’t protect against error. Citing what happened in Mayfield does not advance this argument. By this argument, because the examiners got Mayfield wrong using “identification” then should we abandon the term “Identification”? This is a straw man argument.6) Would these 5 conclusions protect against errors? How would the examiners in the Mayfield case have reported under this proposal? Wouldn’t they still have reported ‘Source ID’ meaning “Source Identification is reached when the friction ridge impressions have corresponding ridge detail and the examiner would not expect to see the same arrangement of details repeated in an impression that came from a different source.” (quoted from the OSAC document)
As you know from your research, we do not expect to see a lot of things but that doesn’t mean they don’t exist (the high erroneous exclusion rate for example).
Correct. There is a subtle difference in its meaning. It really comes down to a philosophical argument about what an ID is. This definition of ID is written to avoid “single source attribution” while dancing around a very complicated issue (that the ID is a posterior belief of the examiner after performing an examination and a belief that the proposed source has a ‘non-zero’ chance of being the source (i.e. he was not dead, in prison, was born, etc. at the time the latent was deposited).7) The OSAC members on the ASB have explained to the ASB that Source ID is not the same as the historic meaning of ID. Is that nuance apparent? In your use of it, are you using the new term ‘Source ID’?
Swiss model (Xena). Yes, indirectly it considers “intervening ridges” but not direct ridge counts. No creases. Discrepancies are handled same way you handle them without a model (subjectively). No palms or foot prints. If an agency is not using a model it is just as easy or difficult as their current job is reaching “IDs” and “inconclusive”.8) You mentioned these conclusions are easier to use with a statistical model. Which model are you using? Does it consider things like the number of intervening ridges, creases or discrepancies? Does the model you’re using work on palm prints or foot prints? If an agency is not using a model, does that mean the 5 proposed conclusions are not as easy to use?
Yes. It is 3 different weights of evidence. The OSAC document already gives that as an option. An examiner may express the degree of “SUPPORT FOR SAME/DIFFERENT SOURCE”. It’s already in the document. The difference is determined the same way you decide it’s an ID versus “Inconclusive with a lot of features in agreement, but not enough to call it”.9) If ‘Support for Same Source’ ranges from limited to moderate to strong support, isn’t that 3 different situations? Why not make those different conclusions to be more transparent? And how is the difference between limited, moderate, strong, and extremely strong support determined? Where would the Mayfield comparison be placed?
How do YOU decide any categorical decision? You evaluate the weight of evidence and determine which category best describes the evidence as YOU have interpreted it, and have supporting data to back up that decision.
I use it in class all the time and students have no problem instantly adjusting and communicating. It’s about increased communication tools.
I’ve used both systems and now testified to both. First hand experience, the OSAC scale is a more transparent, and easier way to communicate, especially marginal, more difficult latent prints.
Yes it IS misleading. It is misleading because it is an error. The problem is not the conclusion, but in the examination. Just as reporting an “EXCLUSION” or “INCONCLUSIVE” would be misleading if there is an identification present to be reported… See CTS 2010 Latent 5D.10) What is Support for Different Sources? If I can’t find consistency, is that ‘Support for different sources? Just because I can’t find my car keys in my house doesn’t mean there is support that they aren’t there. If practitioners report out ‘support for different sources’ in this situation, it seems very misleading.
Your example is conflating two things. Your personal confidence in where to look for correspondence versus the possibility that you are missing the correspondence. If you don’t know where to look or lack complete exemplars then this would be in more of an INCONCLUSIVE situation. (or I prefer Alice White’s “Incomplete” for needing additional exemplars). But if you know where to look and have looked in those areas and have missed the correspondence and report “support for different source” then you are reporting the evidence and you interpreted it. You mis-interpreted it, but it’s as you interpreted it.
Eric and I did a podcast on these conclusions. We both had the same example of Support for Different Source: You find no corresponding features, all signs point towards an exclusion, but your agency REQUIRES, by policy, that you have a core/delta in your latent print to make an EXCLUSION decision.
[And I admit Boyd has a point. There are methods that exist to validate "conclusion scales". That would be an ideal approach. Given that the conclusions we currently use didn't go through ANY such process and given that we used them for decades BEFORE research emerged to performance test examiners.... I'm not too worried about making a lateral shift.]
g.
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Michele
- Posts: 384
- Joined: Tue Dec 06, 2005 10:40 am
Re: Friction Ridge Process Map
No argument here, I can see we’re on the same page. A range of conclusions are preferable and valuable. I think every examiner recognizes that all ID’s are not the same weight and inconclusive has a wide range of reasons for the inconclusive. My agency has been using verbal scales for years (and did a pilot project that lasted over a year, on thousands of cases). We tested it so long that we found things that didn’t work, and other items that needed to be added. Additionally, we still have modifications that could improve the method we’re using even further. The difference between our verbal scale and the OSAC’s is that ours has instructions behind it. When the OSAC instructions come out then I’ll be able to assess if the 5 conclusions are better than what our agency is currently using.
If articulating the weight and transparency are important, then why not articulate the weight of an ID? Isn’t that something that would be more valuable than articulating the weight of inconclusive conclusions?
I don’t think a range of conclusions is a problem for anyone, rather, how to choose the appropriate conclusion and how to articulate those conclusions are the issues at hand. Reporting ‘Support for Source Identification’ when there is limited, moderate, or strong consistency is highly misleading if there is no measure for what is limited moderate, strong or extremely strong. “Consistency exists but not enough to draft any meaningful conclusions” (I.e., inconclusive) seems more transparent to me.
My mention of Mayfield was not to advance the argument. My point was that the goal in changing to 5 conclusions has not been articulated well. If the goal was to reduce errors (which you indicated is not the goal), then my point was that the 5 OSAC conclusions does not meet that goal. This is an important aspect for anyone using the 5 conclusions (these conclusions do not diminish errors).
A few more good takeaways you clarified:
a) using 5 conclusions also does not reduce the subjectivity factor. The 5 conclusions are still subjective at this time.
b) ‘Support for different sources” seems to be added for agencies that are requiring factors that have no basis. That should be added to the document for the sake of transparency.
c) ‘Incomplete’… I thought it was an actual definition from hundreds of years ago stating that something is not final.
Thank you for clarifying all these points. Very educational!
If articulating the weight and transparency are important, then why not articulate the weight of an ID? Isn’t that something that would be more valuable than articulating the weight of inconclusive conclusions?
NOT EVEN CLOSE. I’d advise everyone to take a science class. Scientific conclusions are not merely a scientists opinion. Science requires a systematic approach. Systematic approaches diminish biases and increase consistency. Science also requires testing conclusions, not merely jumping to conclusions. And science reminds us that experience is not evidence. Remember, some people used ‘zero error rate’ for quite a while, and it worked temporarily. That doesn’t mean it was good. Science doesn’t decide methods based on who is advocating for the method, or based on ‘others use it’ (that would be the scientific flaw of appealing to authority). Science wants a systematic approach that has been tested for validity. How do we test it? Put it up against other methods and compare the results. I’d do it myself but I don’t have the instructions on how to use the OSAC method (making it impossible to use or test).How do YOU decide any categorical decision? You evaluate the weight of evidence and determine which category best describes the evidence as YOU have interpreted it, and have supporting data to back up that decision.
I don’t think a range of conclusions is a problem for anyone, rather, how to choose the appropriate conclusion and how to articulate those conclusions are the issues at hand. Reporting ‘Support for Source Identification’ when there is limited, moderate, or strong consistency is highly misleading if there is no measure for what is limited moderate, strong or extremely strong. “Consistency exists but not enough to draft any meaningful conclusions” (I.e., inconclusive) seems more transparent to me.
My mention of Mayfield was not to advance the argument. My point was that the goal in changing to 5 conclusions has not been articulated well. If the goal was to reduce errors (which you indicated is not the goal), then my point was that the 5 OSAC conclusions does not meet that goal. This is an important aspect for anyone using the 5 conclusions (these conclusions do not diminish errors).
A few more good takeaways you clarified:
a) using 5 conclusions also does not reduce the subjectivity factor. The 5 conclusions are still subjective at this time.
b) ‘Support for different sources” seems to be added for agencies that are requiring factors that have no basis. That should be added to the document for the sake of transparency.
c) ‘Incomplete’… I thought it was an actual definition from hundreds of years ago stating that something is not final.
Thank you for clarifying all these points. Very educational!
Michele
The best way to escape from a problem is to solve it. Alan Saporta
There is nothing so useless as doing efficiently that which should not be done at all. Peter Drucker
(Applies to a full A prior to C and blind verification)
The best way to escape from a problem is to solve it. Alan Saporta
There is nothing so useless as doing efficiently that which should not be done at all. Peter Drucker
(Applies to a full A prior to C and blind verification)
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anwilson
- Posts: 28
- Joined: Tue Mar 24, 2015 1:25 pm
Re: Friction Ridge Process Map
My responses are more for the group and aren't intended to single any one person/viewpoint out. I think this discussion is extremely valuable and has already led to some great points. I'm open to any scale that has clear criteria (that have been tested) and can be used to effectively articulate the basis of our conclusions to jurors.
It’s interesting that you say the current conclusions do not communicate the weight of evidence. A lot of agencies use the definitions that were proposed by SWGFAST in their reports. Would you or anyone agree that the SWGFAST definitions don’t communicate the weight of evidence? Also, one of the criticisms of the discipline in terms of conclusions is that agencies report conclusions differently. I'm curious which current conclusions are you referencing? Are you referencing agencies that only report "ID" and "not-ID" or something else?
In my experience talking with other agencies, part of their issue with some of these documents is that they’re being sent out without any support behind them on what was relied upon to make decisions on which wording is “best” or most “transparent”. I think most if not all of us are fully aware of the problems of not providing the reasoning for a decision that’s been made and I personally think the OSACs should be holding themselves to the same level of accountability by which they’ve criticized others. There are members on the OSACs that have testified criticizing agencies for doing the exact same thing they are doing with these documents. Reaching a decision without providing criteria or support behind it.
The argument that verbal scales have been used in other forensic disciplines doesn’t really address the question asked. If an examiner testifies that verbal scales can be used because other forensic disciplines have used them is extremely problematic. While I don’t fully agree with the arguments put forth in the PCAST report, all of those disciplines you mentioned were heavily criticized for the lack of testing that was done. Change shouldn’t occur before testing is performed. Especially if that change affects people’s lives and freedom. The OSACs should be doing the testing for the “standards” they’re proposing and not putting that burden on agencies. They’re the ones being tasked with creating these documents not individual agencies. I fully agree that agencies should perform internal testing on any scale/criteria they use as the basis for the conclusions they report. If the OSACs aren’t going to go through that process prior to releasing documents they are just muddying the waters of releasing documents that sound authoritative that have not been tested for effectiveness of use.4) Have these 5 conclusions been tested to see if other conclusions would be valuable (should there be 6 or 7 or 8 conclusions)?
Not within fingerprints. Verbal scales such as these, to varying degrees, have been used in questioned documents for ages, footwear, trace evidence, facial, basically EVERY forensic discipline except fingerprints. Verbal scales of limited, moderate, strong, extremely strong have been used in Europe in some agencies for 30 years. They have been in use in France, Holland, England, Switzerland for fingerprints. Possibly others that I’m unaware of.
Austin Hicklin addressed this at IAI. How can we test it effectively if we don’t make a change? Or if we test it significantly up front, what validity does it have if people have no reference point not having used the conclusions before. Agencies could do internal testing before adopting it; it would not need to be significant.
I believe Michele’s point is that if those on the OSACs find these conclusions so valuable why aren’t they using them regardless of whether they’ve made it through the ASB? It sounds like you may be one of the only ones on the OSACs using them. I commend you for using them regardless of approval as you clearly find them valuable but what about others on the OSACs? It’s not like agencies aren’t already reporting conclusions that have not been “sanctioned” by the ASB. Your response is just shifting blame away from the OSACs and onto the ASB. My understanding is that the ASBs role is to make sure these documents are useful and improve the discipline. If they haven’t made it through the process, perhaps the issue is that the OSACs haven’t demonstrated their usefulness clearly?5) Have these 5 conclusions been tested to see if they are more transparent? Those proposing them have said they are not using them. If these conclusions are more valuable, why aren’t they using them? I would think they would feel ethically compelled to use the best conclusions whether approved or not.
I can’t speak to why agencies have not adopted them. Perhaps they were waiting for ASB to approve them so they could move forward. Seeing that is not going to happen, I hope agencies begin adopting them without the sanction of ASB.
By definition, they are more transparent because by definition they allow the user to communicate a weight of evidence. The current conclusions do not communicate a weight of evidence.
It’s interesting that you say the current conclusions do not communicate the weight of evidence. A lot of agencies use the definitions that were proposed by SWGFAST in their reports. Would you or anyone agree that the SWGFAST definitions don’t communicate the weight of evidence? Also, one of the criticisms of the discipline in terms of conclusions is that agencies report conclusions differently. I'm curious which current conclusions are you referencing? Are you referencing agencies that only report "ID" and "not-ID" or something else?
While conclusions can’t protect against all error, the criteria used to render a conclusion should be such that it mitigates the likelihood of an error occurring. Mayfield is a great example to cite because a quality standard for methods and conclusions should place the Mayfield comparison at a minimum in an Inconclusive conclusion (ideally in an Exclusion decision) not an Identification conclusion. Michele’s question is still a valid and important question that the OSACs should be asking when drafting these documents.6) Would these 5 conclusions protect against errors? How would the examiners in the Mayfield case have reported under this proposal? Wouldn’t they still have reported ‘Source ID’ meaning “Source Identification is reached when the friction ridge impressions have corresponding ridge detail and the examiner would not expect to see the same arrangement of details repeated in an impression that came from a different source.” (quoted from the OSAC document)
As you know from your research, we do not expect to see a lot of things but that doesn’t mean they don’t exist (the high erroneous exclusion rate for example).
Conclusions don’t protect against error. Citing what happened in Mayfield does not advance this argument. By this argument, because the examiners got Mayfield wrong using “identification” then should we abandon the term “Identification”? This is a straw man argument.
Do you know if the Swiss model been validated? I can’t find any information on it being a validated model (both the math used for the algorithm and its effectiveness of use). One of the criticisms of our discipline is that we are using methods that have not been validated. If someone is using a statistical model that isn’t validated isn’t that just as problematic? If a validation has occurred I’d love to read the validation study. I think more agencies would also be open to using it (if other agencies can even get access to it?) if they could review any sort of validation study that was performed. They could also then perform their own internal testing as well, similar to what agencies do with chemical processing techniques.8) You mentioned these conclusions are easier to use with a statistical model. Which model are you using? Does it consider things like the number of intervening ridges, creases or discrepancies? Does the model you’re using work on palm prints or foot prints? If an agency is not using a model, does that mean the 5 proposed conclusions are not as easy to use?
Swiss model (Xena). Yes, indirectly it considers “intervening ridges” but not direct ridge counts. No creases. Discrepancies are handled same way you handle them without a model (subjectively). No palms or foot prints. If an agency is not using a model it is just as easy or difficult as their current job is reaching “IDs” and “inconclusive”.
How are you basing your view that the OSAC scale is more transparent? Is it more transparent to jurors? Do they have a better understanding of the OSAC conclusions than conclusions used by other agencies? I’d be interested to know how the people tasked with making decisions on the effectiveness of expert witnesses feel about the varying conclusions used. I know Brandon Garrett and William Thompson have been doing some great work with this and I imagine it would be extremely beneficial for the OSACs definitions to be incorporated into similar research. Perhaps that's already being done?I’ve used both systems and now testified to both. First hand experience, the OSAC scale is a more transparent, and easier way to communicate, especially marginal, more difficult latent prints.
In my experience talking with other agencies, part of their issue with some of these documents is that they’re being sent out without any support behind them on what was relied upon to make decisions on which wording is “best” or most “transparent”. I think most if not all of us are fully aware of the problems of not providing the reasoning for a decision that’s been made and I personally think the OSACs should be holding themselves to the same level of accountability by which they’ve criticized others. There are members on the OSACs that have testified criticizing agencies for doing the exact same thing they are doing with these documents. Reaching a decision without providing criteria or support behind it.
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ER
- Posts: 351
- Joined: Tue Dec 18, 2007 3:23 pm
- Location: USA
Re: Friction Ridge Process Map
To those that are argue against the OSAC 5 Conclusion scale because...
- There are no instructions on HOW to use it;
- There has been no validation, testing, or studies using it;
- The conclusions don't protect against errors; or
- Any of the other myriad reasons:
This is a standard for conclusion terms and definitions. Something that DOES NOT EXIST currently. Your arguments would only hold water if the new standard was being compared to an existing standard. It is not. The new standard is being compared against nothing. It obviously wins.
The current conclusions have no instructions for use. Because there are no current standard conclusions.
The current conclusions had no validation, testing, or studies when they came into use. Any validation, testing, or studies that have been conducted have been on conclusions for a single test, a single study, or a single agency. Not on STANDARD conclusions.
The current conclusions do not protect against errors. Because conclusions terms and definitions don't protect against errors. Duh. They just... can't. Like, how your name and SSN can't protect you against meteorites?
In order to progress to standard conclusions a) with instructions for use; b) with validation, testing, and studies; and (well, no conclusion scheme protects against errors, so skip that point)... they must be...
LISTED
DEFINED
STANDARDIZED
Preventing progress on these very basic first steps because subsequent steps haven't been completed is insanity. It's asking the baby to run before she crawls. How can ANY progress be made on standards for the examination process when the standard simply LISTING the conclusions is filibustered into non-existence.
Seriously? Write the examination process standard before we've even decided on the possible conclusions? Insanity!
- There are no instructions on HOW to use it;
- There has been no validation, testing, or studies using it;
- The conclusions don't protect against errors; or
- Any of the other myriad reasons:
This is a standard for conclusion terms and definitions. Something that DOES NOT EXIST currently. Your arguments would only hold water if the new standard was being compared to an existing standard. It is not. The new standard is being compared against nothing. It obviously wins.
The current conclusions have no instructions for use. Because there are no current standard conclusions.
The current conclusions had no validation, testing, or studies when they came into use. Any validation, testing, or studies that have been conducted have been on conclusions for a single test, a single study, or a single agency. Not on STANDARD conclusions.
The current conclusions do not protect against errors. Because conclusions terms and definitions don't protect against errors. Duh. They just... can't. Like, how your name and SSN can't protect you against meteorites?
In order to progress to standard conclusions a) with instructions for use; b) with validation, testing, and studies; and (well, no conclusion scheme protects against errors, so skip that point)... they must be...
LISTED
DEFINED
STANDARDIZED
Preventing progress on these very basic first steps because subsequent steps haven't been completed is insanity. It's asking the baby to run before she crawls. How can ANY progress be made on standards for the examination process when the standard simply LISTING the conclusions is filibustered into non-existence.
Seriously? Write the examination process standard before we've even decided on the possible conclusions? Insanity!