FIG Images on CLPEX - DISCUSSIONS?

[antonroland]

Anybody open for a discussion of any of these images, would like to hear opinions on these.

[Charles Parker]

antonroland, which one would you like to discuss.

Is there one that gives you a real 'Heartache'? I will be glad to discuss one or several.

FIG 14 has been updated.

Some others should be updated soon.

[antonroland]

Charles

If one thing the FIG images have reinforced my belief of showing the complete latent on my comparison chart used during court testimony. Now I don't think I am out of line when I say that, traditionally, South Africa might have had one of the lowest "point standard numbers" at seven points required.

Personally I have always used 13 points over the years and I cringe at anything below 10 when I see some of those FIG images.

Anton



P.S.

Not to dicuss the merits of the Cowans matter here but having just read that thread I do believe that it is sort of relevant here don't you think?

[Gerald Clough]

I really think that what "close calls" and the known erroneous cases have to say about point counts is that there's no reasonable point count so low as to rule out a conclusion and no count so high that it's a sure thing. It is first and foremost about certainty in determining the nature of features that appear in the latent. If one is correct in their interpretation of what they see, only the negligence of entirely missing available detail has more than an invisibly small chance of leading to an improperly drawn conclusion. If your characterization of every feature that adds weight toward the conclusion isn't solid, the conclusion is, to that degree, flawed. I think what we see in some errors is that certainty about some features improperly influences confidence in poorly represented features.

Note the use of "improperly drawn conclusion" above, rather than "error." We tend to focus on error, erroneous identification, because we have, in one way or another, become aware that the indicated individual is not the source of the latent. I think this often leads us to concentrate on the individual feature misinterpretations, gaining a warm feeling because we all now see that those either couldn't or shouldn't be interpreted with confidence and feeling pretty smug about it. (Come on. You know you do.) We should instead be thinking hard about those times when we seem to have been right (the identification having been confirmed by circumstances or confession) but perhaps shouldn't have been concluded. I didn't use "error," because the plain old fact is that we simply don't trade in absolute exclusive 100% certainty. We deal in (hopefully) very high confidence opinion. What matters is that the conclusion was properly drawn from equally high certainty interpretations of what we see.

In other words, we cannot say that an identification is absolute, but we can say that we are absolutely certain we made the identification properly. That's where we recognize the legacy of point counting. Point counting provided a bright-line of certainty, taken entirely on faith because someone speaking with authority said that was the number. But the reality is that it doesn't matter if it's 3 or 30, if you got the count by guessing at features or improperly interpreting them to fit the conclusion suggested by other features. I have long wondered about the effect of sloppy thinking about Q/Q in some well-known errors. The sloppy part is thinking of the Quality scale as being so wide that a great number of features can offset some vary poor quality. But the range of usable quality is really quite narrow. How narrow? Can't say. The "narrowness" is in the critical differential judgment of the examiner, not in some definable standard. The examiner must be able to say: "I characterize this feature in this way, because ___ and there can be no other characterization."

The "fuzz," the slack in the interpretation, is in such things as whether the impressed feature represents a fully connected bifurcation or a hooked ending ridge that nearly connects. (And by "feature," I include all things, ridge flow, ridge count, etc., anything we come to interpret during the examination.) The degree to which the characterization is narrow and very specific or more broad but still representing the same formation and flow is the narrow range of usable quality. If the quality is so poor that the differential interpretations of a feature extend to fundamentally different characters of formation and flow, it's out, and no amount of other features in agreement can bring it into the fold. (I think that in some of the notorious error cases, we have seen examiners do just that, expand the quality window to take in some less likely interpretations.) At that point, a feature may be useless without being a "clear contradiction," but it's out of play as a factor in conclusion. My logic is that, if you can't say what it is, it can't contribute to identification without paradoxically being considered equally a contradiction. Anything else is a frank bias for identification.

I really don't think point counting was such an evil, given the conditions during the time when it was in vogue. I think it's fair to say it carried with it the unspoken and unconsidered reality that comparisons were mostly worked against local collections, and that tended to hit the right crooks, if not always for the right reasons.

[Charles Parker]

antonroland stated

Personally I have always used 13 points over the years and I cringe at anything below 10 when I see some of those FIG images.

Anton when I first started sending out the FIGS I received several e-mails that informed that I had missed marking a point here or there. I very seldom will mark all the ridge characteristics that might or might not be in agreement. Those e-mails just told me that for some the concept of individualization was a particular number of minutias in agreement.

Individualization is more just a set number for me it is the relationship and the configuration of that detail that is the issue. Two ending ridges separated by single flowing ridge has less weight than two ending ridges separated by seventeen flowing ridges or a spur with a dot in the throat is more than three ending ridges.

From the beginning the FIGS were not offered as Identifications or Exclusions but were simply ‘Interesting Comparisons’. Each person looking at them had to decide that issue based upon their knowledge, training and experience. The main objective of the FIGS was to create thought and discussion. From some of the e-mails I have received over the past two years I would say that some of the FIGS have done just that and created discussion and thought.

The bottom line on the FIGS is that they are interesting comparisons----nothing more and nothing less.

You still want to discuss one I will be more than happy to. Some that probably brought the most discussion to the top is FIG 14, FIG 22 and FIG 35. FIG 35 is one that pretty much split the vote between the three conclusions. It generated a lot of discussion at one point.

antonroland stated

Not to dicuss the merits of the Cowans matter here but having just read that thread I do believe that it is sort of relevant here don't you think?

I am not sure I undestand your question.

Charles

[antonroland]

Charles

I understand and agree with your statement regarding the FIG images...thing is, for lack of better understanding many of my colleagues have traditionally placed (and to a point still do place) a specific number on an individualization.

Personally I would like to steer away from L1, L2 and L3 in line with the U.K. decision of Nov 2004. Some of my colleagues have considered further detail but few have ever had a way to articulate their observations in this regard.

I am about to embark on printing these and distributing them among colleagues for regular discussions.

I would love to discuss those you mentioned but work load does not allow me to do it now...will get back to you soon.

Gerald: Thanks for your post here, I will read it later as it is a bit long but your responses are always worth reading properly.

Have a great day all!

[Charles Parker]

antonroland stated

Personally I would like to steer away from L1, L2 and L3 in line with the U.K. decision of Nov 2004.

Perhaps someone can expound further on antons statement. I remember reading something a while back on the discussion of L3D in the U.K. and that if I remember correctly some in the U.K. were not going to adopt L3D in reference to Friction Ridge Individulization.

I do not remember what the outcome was but in reading between the lines in anton's statement I take it that the U.K. does not use L3D or support its use.

Is this true? Can someone elaborate?

[antonroland]

Just happened to pop into the office and saw the reply

See "Features" in Michele Triplett's dictionary site here:

http://www.fprints.nwlean.net/f.htm

Cheers all

[David Fairhurst]

The issue of the UK decision is simply one of terminology not of examination process.

It was recognised that Ashbaugh's categorisation of friction ridge detail into 3 levels is arbitary (though no less valid or useful) and that uniqueness is apparent in a continuum of features of differing sizes from individual ridge units with pores, which make up ridges with ends and forks, which combine to make unique patterns. (let's not forget that any pattern classification system is also arbitary and used only to help file fingerprints in small groups to aid searching - every pattern is unique.)

Quite simply, UK examiners use 3LD, we just don't (officially) use that term.

Personally I wish we had continued using Ashbaugh's simple terminology. I think the decision not to had more to do with the personalities involved than with making things easier to understand and communicate in the global fingerprint community.

David

[Charles Parker]

David, thanks for clearing that up. I thought I had remembered where I had read that in Fingerprint Whorld but could not remember the outcome.

The word ‘features’ reminded me of an article written by John Nielson titled the ‘Identification Process’ and was published in the September 1988 issue of the ‘Identification News’. I love that article and use to have it as required reading in a training program. Since it is dated a little now I have relegated it to supplementary reading.

In that article Mr. Nielson recommended the use of the word ‘Event(s)’ and even had a quote from Galton’s book on his use of the word ‘event’. I have used it a number of times since I read the article back in 1988. About two years ago during a Pre-Trial Conference with an A.D.A. preparing for trial I subconsciously used the word ‘events’ and the A.D.A. asked me to explain. After my description she asked me to use the word ‘event’ and not ‘points or ridge characteristics’ in the trial. I pointed out to her that the word ‘events’ was not generally accepted in the discipline and she stated she did not care but she thought the word would be a better description to the jury and that the word ‘points’ was a word that just had too much of a number attached to it.

So I did and it went very well and we got a conviction. Last year I had another trial with the same ADA and one of the first things she asked me was to use the word ‘events’ and not ‘points’ as it was more appropriate and sounded better. So I did a second time and was never quizzed by the defense on its use.

However I think I like the word ‘events’ better than the word ‘features’.

But hey, whatever ‘Grinds your Gears’.

Again thanks for the additional information on the U.K. It is always nice to know how others are doing things.

PS—I wonder if John Nielson would update that article!