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Monday, July 9, 2007

 
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Breaking NEWz you can UzE...
compiled by Jon Stimac

Fingerprints Reveal Injured Suspect's Identity  FT WORTH STAR TELEGRAPH, TX - July 6, 2007 ...prints tipped off police to the real name of a wounded man who was dropped off at a hospital...

Fingerprint Science Centenary Marked YORKSHIRE POST, UK - July 5, 2007 ...a century of forensic science is being celebrated at a museum with a new exhibition...

Judge OKs Request for Fingerprints of Slaying Suspect  SOUTH BEND TRIBUNE, IN - July 2, 2007 ...judge granted permission to prosecutors to fingerprint accused murderer...

FBI Vet: Fingerprint Matched Suspect's CHICAGO SUN TIMES, IL - July 2, 2007 ...retired FBI fingerprint analyst testified that a fingerprint from reputed mobster appeared on an application...

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Last week

We continued a series on latent print reporting, the process, conclusions and error.  We discussed milestones along the path of crime scene to the Analysis phase of ACE-V that can negatively affect what would have been a conclusive outcome.

This week

We conclude the series with the second half of a discussion of errors in the latent process.

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Errors in Latent Print Examination - Part 2
by Kasey Wertheim

The final exercise in our series on latent print process is to consider error for all possibilities involving sufficient similarity or sufficient dissimilarity for a conclusion to 2 possible ground truth states: matching or non-matching prints.  To accomplish that, we have arrived at this point in the process having determined the following state:

A latent print is considered suitable for comparison by that examiner. Upon a comparison of the latent print, it may be determined that in fact the impression is not suitable for a conclusion.  However, the definition of "suitable for comparison" is set upon the principle that the act of comparing a print establishes that it is comparison quality.  Whether similarity or dissimilarity is suitable for a conclusion is the subject of this week's detail.

The known print is considered suitable for comparison by that examiner.  Generally, the vast majority exemplar prints are suitable for comparison.

Suitable common area and orientation has been achieved.

For the 8 possible scenarios below, it is critical that we have already determined these 3 conclusions.  In some cases we will proceed to comparison and evaluation and cycle back to our hypothesis involving orientation and common area.  Sometimes during the comparison itself we encounter additional information that changes our evaluation.  All subsequent steps in the latent process would be repeated and the new information would be incorporated into the hypothesis and decision making process.

For the 2 hypothesis sets of evaluation listed as Hs6, 8 scenarios are possible:

For matching prints:
A1) Correct match
A2) Incorrect match
A3) Correct Inconclusion - similarity
A4) Incorrect Inconclusion - similarity

For non-matching prints:
B1) Correct exclusion
B2) Incorrect exclusion
B3) Correct Inconclusion - dissimilarity
B4) Incorrect Inconclusion - dissimilarity

For the presence of similarity, the examiner's hypothesis and null hypothesis are:

Hs6B: Sufficient Q/Q of similarity (agreement) of detail does not exist to establish individualization.
H0: Sufficient Q/Q of similarity (agreement) of detial exists to establish individualization.


For prints that match, if the examiner accepts the null hypothesis by concluding that there is agreement to individualize, two scenarios are present: Either the examiner was A1) correct or was A2) incorrect.  If the examiner rejects the null hypothesis by concluding that there is not agreement to individualize, then two scenarios are present: Either the examiner was A3) correct or was A4) incorrect.

A1) Correct Acceptance of Agreement to Individualize - The examiner has correctly identified a print that matches.  There is no technical error - the null hypothesis was correctly accepted.  The examiner acted in an acceptable manner.  Real world result: The right bad guy is convicted.  Agency action: none necessary.  No recommendations.

A2) Incorrect Acceptance of Agreement to Individualize - The examiner has incorrectly determined there was agreement to individualize.  The print could NOT and should NOT have been identified by that examiner based on his/her ability level, but it was.  The ground truth was that the prints were made by the same source, but in reality the examiner was not able to confidently arrive at this conclusion.  There is technically no error because the prints actually were made by the same source.  The key is that the latent print in question was compared and was therefore considered of comparison quality by that examiner, but the final evaluation should have resulted in an inconclusive determination instead of a match determination based on the ability of the examiner.  If the examiner had more ability, this might become scenario A1, but the examiner did not have that ability because accept of the null hypothesis was in error.  A possible scenario might be the only print in a major case and the examiner "pushed the envelope" and guessed correctly.  Another possible scenario might be an examiner who knowingly verifies an identification that is outside his/her comfort level.  In statistics, this would be considered the more serious "Type I" error of commission.  The examiner incorrectly accepted the null hypothesis when it was actually false.  However, in reality this type of error would not necessarily be discovered.  Furthermore, this scenario would be difficult to prove, since no valid and reliable methods are widely used to quantify and compare examiner ability and latent print difficulty.  Besides, who would say anything... it was, in reality, a correct "guess".  There is scientific and statistical (type I) error.  The examiner acted in an unacceptable (and in fact an unethical) manner.  Real world result: The right crook goes to jail.  Agency action: difficult to discover, document, and take action so most likely, none would occur.  But it is recommended that agencies be aware that this problem can exist and take measures to address this scenario in policies and procedures with defined methods of discovery through QA/QC with appropriate corrective action.  Disciplinary action may be considered in this scenario because the examiner knowingly acted in an unethical and unprofessional manner.

A3) Correct Rejection of Agreement to Individualize - The examiner has correctly determined that there was not a sufficient volume of similarity present in sequence to individualize.  The print could not and should not have been identified by that examiner based on his/her ability level, and in fact it was not.  There is no error because the identification was not within the ability range of that examiner.  Technically the print was made by the same area of the same source being compared, but the similarity that was present was not sufficient and therefore the match was not 'called' by the examiner.  THIS SHOULD NOT BE CALLED A 'MISS'.  A miss would occur when that examiner could have and should have made the match but did not orient the print correctly or otherwise compare the area in question.  In this scenario, it is true that the prints were made by the same source.  It is also true that the examiner was looking at the correct area of the known print of value, and they saw similarity that was present.  However, in the opinion of the examiner, based on his/her ability including training, experience, etc., it was simply not enough to individualize.  This is OK!!  The print may have been valuable for exclusion, and may have even been excluded to other fingers in the case by the same examiner.  Although of value for comparison, the print in question should have been deemed unsuitable for purposes of individualization, and it was - it was not identified.  Distortion may also have co-existed for which that the examiner could not or would not account.  In the field of latent prints, there is no error; the print is considered not suitable for individualization by that examiner and
the examiner made a correct determination for their ability level.  In statistics, there is no error - the examiner correctly accepted their hypothesis   From an ethical perspective, the examiner acted in an acceptable manner.  Whether or not this level of performance is acceptable is either an issue that should be addressed in agency policy/procedure, or a decision that supervisory personnel should be prepared to discuss and decide on a case-by-case basis.  Real world result: The right crook does not go to jail.  Agency action: either accept current performance level or provide additional training to increase performance level.  Also, either report the comparison as inconclusive or assign it to another examiner within or outside the agency, depending upon agency policy.  If procedures are in place to deal with this scenario and the impression is identified by other examiners, the real world result may change to the right crook going to jail.  Disciplinary action for the examiner in this scenario is not warranted.  Corrective action may include additional training or assignment to other duties depending on the history of the individual.

A4) Incorrect Rejection of Agreement to Individualize - The examiner has incorrectly determined that there was not a sufficient volume of similarity present in sequence to individualize.  The print could and should have been identified by that examiner based on his/her ability level, but it was not.  Possible scenario: the suspect was a friend, acquaintance or family member and the examiner was not objective.  Another possible scenario: the examiner was asked by an officer or co-worker not to identify a print that matched.  THIS IS AN INTENTIONAL ERROR.  In statistics, this would be considered the less serious "Type II" error of omission - the examiner incorrectly did not accept the true null hypothesis when they should have.  The examiner acted in an unacceptable and unethical manner.  Real world result: The right crook does not go to jail.  Agency action: hopefully verification or QA/QC would reveal this error.  P
roving that an examiner intentionally called a print "no value" or "inconclusive" when they knew it matched would be difficult to prove, since no valid and reliable methods are widely used to quantify and compare examiner ability and comparison difficulty.  It is recommended that agencies be aware that this problem can exist and take measures to address this scenario in policies and procedures with defined methods of discovery through QA/QC with appropriate corrective action.  Disciplinary action may be considered in this scenario because the examiner knowingly acted in an unethical and unprofessional manner.

For the presence of dissimilarity, the examiner's hypothesis and null hypothesis are:

Hs6B: Sufficient Q/Q of dissimilarity (disagreement) of detail does not exist to establish exclusion.
H0: Sufficient Q/Q of dissimilarity (disagreement) of detail exists to establish exclusion.

If the examiner accepts the null hypothesis by concluding that there is disagreement to exclude, two scenarios are present: Either the examiner was B1) correct or was B2) incorrect.  If the examiner rejects the null hypothesis by concluding that there is not sufficient disagreement to exclude, then two scenarios are present: Either the examiner was B3) correct or was B4) incorrect.

B1) Correct Acceptance of Disagreement to Exclude - The examiner has correctly excluded a print that in fact does not match.  There is no error.  Real world result: contact may or may not have been made with that item of evidence, but contact is not proved.  The examiner and agency should be aware that this conclusion may be used in an attempt to disprove contact, but this conclusion alone does not disprove contact.  Agency action: none necessary.  No recommendations necessary.

B2) Incorrect Acceptance of Disagreement to Exclude - The examiner has incorrectly determined there was sufficient dissimilarity present in the impression to exclude.  The print could NOT and should NOT have been excluded by that examiner based on his/her ability level, but it was.  There is technically no error because the prints did not actually match.  A possible scenario might be an unethical defense witness who wants to cast doubt on the case, so he/she chooses an impression that is not actually of value and proceeds to exclude the defendant as a possible donor of that impression. 
A casework scenario would be an examiner who kept a borderline impression that was not suitable for comparison just because it was the only latent in the case, but reported an exclusion.  It is noteworthy that this scenario would have to also coincide with an error in Analysis Hs2, Comparison Hs3, or Hs4.  It is impossible based upon an examiners ability that the non-matching impression be correctly considered suitable for comparison against suitable known prints in a common area, yet the examiner cannot correctly find sufficient disagreement to exclude.  One of the first 3 states would have to not exist: that the impression is suitable for comparison, that the area is present in the known print, or that the known print quality is suitable.   In statistics, incorrect acceptance of the null hypothesis is considered the more serious "Type I" error of commission.  The examiner incorrectly accepted the null hypothesis that was actually false.  Real world result: contact may or may not have been made with that item of evidence, but contact is not proved.  This conclusion may be incorrectly perceived as disproving contact, but this conclusion alone does not prove or disprove contact.   Agency action: this scenario would be difficult to prove, since no valid and reliable methods are widely used to quantify and compare examiner ability and latent print difficulty.  Besides, who would say anything... it was, in reality, a correct "guess" and did not involve a match.  There is scientific and statistical (type I) error.  The examiner acted in an unacceptable (and in fact an unethical) manner by retaining and effecting a conclusion on a print that was not suitable.  It is recommended that agencies be aware that this problem can exist and take measures to address this scenario in policies and procedures with defined methods of discovery through QA/QC with appropriate corrective action.  Disciplinary action may be appropriate dependent upon the circumstances in the case and the history of the employee.

B3) Correct Rejection of Disagreement to Exclude - The examiner has correctly determined that there was not a sufficient volume of dissimilarity to exclude.  The print could not and should not have been excluded by that examiner based on his/her ability level, and it was not.  There is no error because the print was not suitable for comparison purposes.  Technically the print was not made by the same area of the exemplar being compared, but there was not sufficient dissimilarity to exclude and therefore it was not excluded.  The print in question was deemed suitable for comparison purposes at Analysis Hs2, was kept as suitable for comparison, and it was compared by the examiner to the correct area of a known print of suitable quality.  By reaching this point the examiner has concluded that the print is actually not able to be excluded from this finger, and should report it as "unable to exclude".  Some similarity may also co-exist between the latent print and the exemplar for which the examiner cannot account.  Real world result: wasted time and contact not proved or disproved.  Agency action: none necessary as long as the impression is reported as unable to exclude.  Recommendation: use this scenario as an example that keeping and comparing prints not suitable for exclusion wastes time and proves nothing.

B4) Incorrect Rejection of Disagreement to Exclude - The examiner has incorrectly determined that there was not a sufficient volume of difference to exclude.  The print could and should have been excluded by that examiner based on his/her ability level, but it was not.  Possible scenario: the examiner works for an agency that won't allow them to keep any impression that falls short of containing a sufficient volume of detail for individualization.  In this scenario, the examiner may see a whorl pattern in blood on the murder weapon, but does not exclude the only major suspect with no whorls, because they have been instructed that it is not an acceptable practice to keep impressions you cannot identify, even if you can exclude them.  In the field of latent prints, there has been recent heated discussion on this concept.  Scientifically, this would be considered a Type II error of omission because the examiner failed to accept a null hypothesis that was true.  The examiner knew the print didn't match the subject, yet he/she did not report the exclusion.  Some would even argue that reporting "no latents of value for identification were developed" instead of "latent A was not made by person B" would fall into this scenario.  The real world result is that an exclusion could have happened that did not happen, but touch to the item would have neither been proved nor disproved either way.  However, some examiners would argue that not reporting this type of evidence is the same as withholding exculpatory evidence from jury consideration.  Although the exclusion would not disprove touch, it may be one of many factors the jury would consider in a determination of guilt or innocence.  Agency action: it depends on how the agency views their responsibility to report exculpatory evidence.  The examiner did not report a conclusion that was possible - actions may include anything from counseling to revision of policies and procedures to corrective or even disciplinary action.

There is often administrative controversy surrounding cases where the examiner's report is unclear as to whether his result was conclusive.  This goes back to our discussion of verbiage stating that "no identification was effected" representing both exclusions and inconclusive results.  If follow-up comparisons to complete exemplars reveals a match, and it was assumed that the prior phrase was exclusionary, the two reports would appear to many officers to conflict.  This is the reason why many agencies have moved to or are considering exclusionary wording for latent prints that were compared to complete friction ridge exemplars.  Even if no palm prints are present, some latent prints are obviously made by the end joint of the finger and can be excluded as being the fingerprints of the subject.

In reality, the definition of exclusionary report verbiage and incorporation of the practice into the identification unit ultimately holds the examiners to a higher granularity of conclusions.  This forces the examiner to go beyond just finding the matches and instead further define whether exhaustive comparisons excluded the impression from having been made by the subject.  With increasing scrutiny of the latent process both within and outside of our community, going are the days that some examiners hide behind the veil of confusion surrounding whether phrases like "no identification was effected" are conclusive.  On this topic, see also The Detail # 78: Inconclusive Opinions, The Detail # 80: Inconclusives.

In verification, all elements of ACE are objectively repeated by another competent examiner.  The same errors apply to the second examiner.  It is noteworthy that two examiners may arrive at correct conclusions and differ in opinion.  For example, if one examiner correctly determines that a comparison is a match based on a high level of ability (A1), but another examiner correctly determines that the comparison is inconclusive (A3) this situation is not considered a major problem in the latent print community.  The agency or administrator may determine the root cause of the issue and recommend additional training, for example.  Likewise, if one examiner correctly determines that a comparison is an exclusion based on a high level of ability (B1) but another examiner correctly determines that the comparison is inconclusive (B3) and therefore of no value for comparison, this is not considered a major problem.  Differing levels of ability exist within our discipline.  However, the situation cannot exist where one examiner correctly determines agreement for individualization (A1) and another examiner determines disagreement for exclusion (B1).  In this case, either the agreement being used by examiner A is not truly agreement or the disagreement being considered by examiner B is actually distortion.  Given recent high profile erroneous identifications, this is an area that should be further studied and discussed within the community.  What is our level of tolerance as a community for an examiner that erroneously considers similar features to agree to the level of individualization?  What is our level of tolerance for an examiner that erroneously considers distortion to disagree to the level of exclusion?  Is our tolerance of erroneous individualization less than our tolerance for erroneous exclusion?  Is erroneous exclusion acceptable in our discipline?

As we conclude our discussion of errors associated with the latent print process, it is appropriate to state that for every error, there is a reason it occurred, a responsible person(s) and corrective action that should be taken to avoid the error in the future.  The goal of any administrator dealing with an error is to determine the root cause of the issue and change processes and procedures to prevent the root cause and therefore it's consequence from occurring in the future.  Some root causes may be extremely distanced from their effect.  Take for example the well known six sigma example: The corrective action to stop disintegration of the Washington Monument was to turn on the lights later into the evening.  How on earth did they establish that action?  Follow their 5 why's:

Why was the monument disintegrating?  Because of the use of harsh chemicals.
Why were harsh chemicals being used?  To clean up stains from pigeon... um... yeah.
Why were there so many pigeons?  Because there were a lot of spiders to eat.
Why were there so many spiders? Because there were a lot of gnats to eat.
Why were there so many gnats? They were attracted there by the monument lights at dusk.

For more on the 5 why's, visit http://www.isixsigma.com/library/content/c020610a.asp.

Applying this principle to a conflict, we might ask 5 why's:

Why did the examiner incorrectly conclude exclusion?  Because of one dissimilarity.
Why did the examiner view this event as a dissimilarity? Because they did not recognize it as distortion.
Why did the examiner not recognize distortion? Because they had never seen that type of distortion before.
Why had they not seen that type of distortion? Because they had never been to a course in distortion.
Why had they never been to a distortion course? Because a good one had not existed prior to Alice Maceo.

We could continue, but you get the main point - without Alice where would we be?  just kidding.  Seriously... there is a root cause to everything.  Once we establish the correct conclusion, our reaction to conflict and error needs to always go beyond the immediate situation to the root cause with the intent of constructive and corrective action.  In our discipline, the opportunity to deal with different types of conflict arises from time to time.  Usually, this deals only with inconclusive results that are acceptable in the discipline.  Once in a while ethical issues are uncovered.  And very rarely do we have differing conclusions on opposite ends of the spectrum.  But regardless of where the error occurs, through a good understanding of milestones in the latent print process, administrators will be in a better position to assess the urgency of conflict as well as define and respond appropriately to error.

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Until next Monday morning, don't work too hard or too little.

Have a GREAT week!