The whole is not always the same as its parts

You are going to buy a new home.  The house is 2000 square feet on a 3/4 acre lot.  You hire Rich (the termite inspector) to check it out before you buy. After all, no one wants to buy a house with termites. 

  • Good news!  The house passed.  No termites.  Thus, you buy the house.
  • Bad news!  A month after the sale closes you discover - termites.  

What?  How could this happen?

 
You go back and look a little deeper in the method of inspection Rich relied upon.  You find out his methodology was to only check "one square inch" of the floor in the house.  When he did not find anything wrong within the "one inch" he assumed everything else was also termite free.
 

How do you feel now?
 
A part of something does not always represent the whole. Determining how many termites are in "one square inch" of a house does not really answer the question whether you have a termite problem.
 
The termite inspector committed what logicians call the all things are equal fallacy.  This occurs when when it is assumed, without justification, that conditions have remained the same at different times and places.
 
The same danger is present when attempting a forensic measurement.  For example, in a typical DUI case where a blood sample is taken, the lab will test less than a M&M size sample of blood.  However, in Arizona the legal definition of an alcohol concentration is grams per 100 micro-liters. Translation, the legal definition of an alcohol concentration requires multiplying the results of the "one inch" by about 1000 (assuming the M&M is about 100 micro-liters).
 
The danger is assuming the rest of 1000 micro-liters (or 100 milliliters) has a proportional amount of ethanol in it.  Small errors multiplied by 1000 can easily mislead you to believe that a person's alcohol concentration is above a legal limit when it is not.
 
Like the termite inspection, it is up to the crime laboratory to prove their justification for assuming using such a tiny amount below the legal definition of an alcohol concentration answers the question - is the person above the legal limit?  After all, no one wants termites...or people being wrongfully convicted.
 
 

Arizona Supreme Court: Scottsdale Crime Lab Update

Tomorrow around 10:00 a.m. the Arizona Supreme Court will issue its decision regarding the Scottsdale Crime Lab.  Here are some of the new stories about the case of STATE v HON. BERNSTEIN/HERMAN:

I will provide a summary of the Supreme Court's opinion following its release.

Lawrence Koplow

Measuring and Counting

 MEASURING

Measuring is the assignment of a number, and all the uncertainties of that of that number, to something.  The purpose of assigning a number is to give meaning to the object measured.

  • Uncertainty: A bag placed upon a scale shows its weight to be 41 pounds.  If the bag must be less than 50 pounds, then the number produced by the scale indicates it meets this requirement.  However, you must know how far from its true value might the 41 pound number be off by?  Uncertainty is the amount of doubt (e.g. the amount of possible variation) you should expect that number might be off.
  • Fit for Purpose: Assume there are two scales.  The same bag weighing 41 pounds is place on both scales.  However, it was determined that Scale A produces numbers that can be off by as much as 30 pounds.  It was also determined that the number produced by Scale B merely off by as much as 3 pounds.  Knowing the amount of uncertainty contained in the number helps distinguish counting from measuring.  Knowing the uncertainty allows you determine if the measurement is fit for the purpose of determine if the object exceeds 50 pounds.

Measuring relies upon estimation.  The choice of data, the methodologies employed, and level of quality measures used tells you how confident you can be in the estimation.  Once you have a reliable estimation of how close a number may be (or not be) to the true value, you can make informed decision as to what purposes the number can be used - and not used.  

 

COUNTING

Counting is not the same as measuring.  However, the two are often confused.  Counting is usually a technique within a measuring process (methodology).  Counting can result in an exact number.  However, measurement will never claim to represent a true value. Measurements are merely estimations.

Counting an exact amount of something is often not possible or practical.  The thing you are intending to measure (the measurand), the matrix it is found in, or the level of accuracy required may make counting impossible.   Thus a system is needed to provide a reliable estimation which you can rely upon.  

Some things to take into account when making an estimation:

  • Distinguishing: Some molecules are so similar to others that it is often impossible continuously distinguish them from each other.  Thus, they cannot be easily counted.
  • Location: Some substances are contained in places we cannot practically enter to count them.  The best way to know how much alcohol is affecting a person's brain at a particular time would be to take a sample of brain tissue.  However, society has not yet determined such a procedure falls outside the protections of a person's 4th Amendment rights.
  • Gas Chromatographs: The results of a gas chromatograph are often used to determine whether a person's alcohol concentration is above a legal limit in DUI cases.  However, the machine does not measure a person's blood alcohol concentration.  If properly used, the machine merely counts the number ethanol molecules in a gas portion of a headspace vial.  Thus, it indirectly counts a microscopic amount ethanol from a tiny sample.  

A measurement based upon a machine's indirect count of a substance results from combining it with algorithms, numerous assumptions, and historical data regarding the past performance of the machine (and software) used in the process.  This is known as an uncertainty calculation.

In this manner, measuring requires much more than counting.  Measuring requires more than merely assigning a number to an object.  More importantly, one can assign a number to an object but not create a measurement.  When this occurs it is not a measurement.  It is a misrepresentation.

 

Counting is what you do to get a number.  Measuring is what you do if you want to know the truth about the number.

Scottsdale Crime Lab: The Supreme Court's Statement of Issues

Today at 11:00 a.m. the Arizona Supreme Court will hear oral arguments regarding whether to reinstate a trial court's finding that - blood alcohol measurements created by the Scottsdale Crime Lab are unreliable.  You can read a history of this litigation by clicking here.

A case being selected by the Supreme Court for review is a rare event.  Simple math shows it is unlikely that any particular case will be reviewed by the Arizona Supreme Court.   The Court receives a substantial amount of “Petitions” to review lower court decisions, but it only selects a small percentage of them each year.  However, because the issues in this case (it is actually a consolidation of 11 cases) will have wide-ranging consequences, it was an ideal case for the Court to review.  The final ruling by the Court, regardless of who prevails, will likely affect how scientific evidence will be handled by Arizona courts for years to come.

While both parties have their own opinions as to what the key issues are, the Court will provide a summary and statement of the issues from their perspective prior to the oral argument.  Last week, as expected, the Court issued its written statement.  Below are the issues as stated in the Court’s summary:

 

1. Did the Court err by holding that Rule 702(d) challenges are excluded from judicial gatekeeping scrutiny under Arizona law?

 

2. Did the Court err in using the accuracy of the results as the criteria for a gatekeeping analysis instead of using the trustworthiness of the methodology used to generate the results?

 

3. Did the Court err in substituting its own judgment for the trial court’s without finding that the trial court’s decision constituted an abuse of discretion?

 

After reading this statement of the issues, one could jump to a conclusion from the way the issues are framed, that the Court is leaning in a particular the direction.  A word of caution – no one knows how the court is leaning.  The Court’s final opinion could easily list a different set of issues.

Today’s oral argument is being held at Arizona State University Law School.  The argument is open to the public and starts promptly at 11:00 am.  Everyone is welcome to attend – regardless of which side of the argument you are on.

The Scottsdale Crime Lab cases will be reviewed by the Arizona Supreme Court

The Arizona Supreme Court has decided to review the Court of Appeals' (COA) ruling regarding whether Scottsdale DUI results can be trusted.  

Our ongoing legal battle over the defective software used by the Scottsdale Crime Lab (SCL) to measure BAC levels begins its final stage.  The Supreme Court granted our request to review the COA's decision permitting prosecutors to rely upon the measurements generated by this software as a basis for a DUI conviction. 

 

WHAT HAPPENED?

Over three years ago a few chromatograms (a graphical representation of a blood alcohol measurement) escaped the Scottsdale crime lab (SCL).  It was something we had never seen before. The floodgates of evidence showing forensic malpractice soon opened.  

We learned, that for several years, the SCL had known of serious defects in the software used to measure BACs.  These malfunctions include assigning an incorrect result with the incorrect person (i.e. John gets Fred's result).  No one in the lab had the expertise to explain why this was occurring, or how to "fix" it.  According to an internal email we obtained from the SCL, they "buried" this from the rest of us.

Even after the defense brought this to light, the Prosecution continued to prosecute the public using this unreliable software.  The penalties for those convicted include mandatorily incarceration and significant monetary fines (a portion of which the crime lab receives).  They are currently still using these defective measurements to incarcerate people.

 

HOW DID WE GET HERE?

There were two primary venues for these debates: 

 

(1) Superior Court; and 

 

(2) Scottsdale City Court.  

 

The Superior Court (felony cases) is where these rulings originated.  The City of Scottsdale courts took a different approach.  That story will be addressed in a separate post.  In the Superior Court, the main case is State v. Herman (on appeal titled In Re Bernstein).  There were two challenges in "Herman" that ended up in the COA.  

 

Herman #1 (Re: Discovery) 

Because we only had access to the initial documents that appear to have been allowed out of the SCL by accident, we did not know the scope of the problem.  

We convinced two Superior Court Commissioners to hold a joint hearing.  They agreed with our arguments and issued an order to produce all chromatograms from 2011.  The Court also gave the Lab almost two months to provide them.  The deadline came and went.  The SCL admitted they did not even attempt to comply with the order.

We filed a Motion for Contempt.  The prosecution filed a Special Action asking the COA to reverse the order.  The morning before the contempt hearing, the COA stayed everything.   A few months later...

  • Result - COA reversed 

We did not get the data.  Today, the scope of the malfunctions still remains unknown. 

 

Herman #2 (Re: Reliability) 

After the COA's ruling, we requested a Daubert (reliability) hearing with the trial court.  This would be Arizona's first substantive Daubert hearing (fortunately, the evidence Rules changed in 2012 to permit such a hearing).   Combined, it lasted almost nine (9) months.  To our surprise, we ended up getting material information in the Daubert hearing (Herman #2) that we did not even think to request in Herman #1. 

At the same time, the Arizona Republic started to investigate our claims.  Through their public records requests (and later our own) a treasure trove of damming evidence was obtained.  

At the hearing, SCL personnel were testifying they understood the issues and put forth an “all was well” message.  However, in contrast to their testimony, the Arizona Republic obtained internal emails, that told a much different story than “all is well.”  Their "private" communications showed the court that the SCL personnel testifying, were less than forthcoming about the severity of the problems and their ability to comprehend them.

The combination of SLC personnel’s tainted testimony, and the testimony our forensic experts (including an independent forensic toxicologist, a certified quality assurance lab auditor, a and forensic software engineer), presented a powerful case that the SCL’s measurements and supporting testimony were not trustworthy. 

 

Arizona Court of Appeals 

As in Herman #1, the prosecution turned to the court of appeals for relief. 

Again, as in Herman #1, it was provided.  

  • Result - COA Reversed.

 

Arizona Supreme Court

Over a year ago, we filed a Petition with the Arizona Supreme Court requesting that they: 

 

(1) review the court of appeals decision; 

 

(2) and reinstate the trial court's ruling.

 

A few weeks ago, the Arizona Supreme Court decided to review the matter.

 

WHAT'S NEXT.

The Court's decision merely means they granted part one of our request: they will hear the case. They have set oral argument on February 17, 2015 at 11:00 am.  It will be a road game for the Court, as it will be held at ASU Law School.  The oral argument is open to the public, but it is expected to be a full house.  If you want to attend, get there early.

 

Lawrence Koplow

You have a bandwidth problem

An analyst from a crime lab testifies that a defendant, who is charged with DUI, has a blood alcohol concentration of .120.  Despite the legal requirements that the state must prove the test is trustworthy, most jurors have made a blink judgement the that test is correct.  As is often the case, the appearance of science is a powerful tool of persuasion.  This is true  even when the opinion is based upon junk science.
 
Here, despite the claims of the analyst and unbeknownst to the jury, the test result was done using unreliable equipment relying on defective software.  Your challenge: undo the jury's initial judgments, demonstrate the analyst is too biased and lacking the qualifications to understand the severity of the equipment's defects, and show the result can't be trusted.  This is no small task.
 
This task will take time.  It requires a thorough understanding of the many underlying scientific disciplines involved.  Adequately educating the jury will require information from several different sources.  Each piece of evidence will present a different evidentiary challenge.  In short, beyond the inherent difficulties of such cases, you also have a bandwidth problem.
 
Bandwidth is the amount of data that can be transmitted in a fixed amount of time.  DUI trials have time and evidentiary limitations.  There are not intended to be semester long science classes.  There are practical realities inhibiting you from properly educating a jury with the knowledge they need to debunk these unsound claims.  If left unaddressed, a court may not even recognize this bandwidth dilemma.
 
Consider the problem in the following terms.  A presentation that does not reach the audience persuades no one.  If Netflix creates next years best new drama, but there is not enough bandwidth to stream it, then what was the point of creating it.  No one pays a subscription fee to see a "buffering" message.  Quality is meaningless without bandwidth.
 
Being right is does not convince a jury without an adequate opportunity to present it to a jury.   In these cases, you don't have a right or wrong problem - you have a bandwidth problem.  Accordingly, neglecting the bandwidth argument can be fatal.  If you don't sufficiently address this issue, then no one may hear how right you are.

A reported result versus a complete result

 

In DUI cases, a machine called a gas chromatograph is often used to measure an alcohol concentration in a blood sample.   The measurement, which the machine prints at the end of the process, is called a reported result.  We are finally at the point in Arizona, where courts are starting to recognize that merely providing a reported result is not sufficient evidence.  The law is coming to the same realization that science did many years ago: a reported result from a machine is an incomplete measurement.

A complete measurement includes more than just a reported result.  As a matter of fact, simply providing a reported result is often misleading.  A reported result is only complete when accompanied by a “statement of its uncertainty.” See NIST Technical Note 1297, 1994 Edition.  No measurement is perfect.  The result of any measurement is only an estimation of its value.  A “statement of uncertainty” is the range of doubt that exists regarding a measurement.

A complete test result, must also include:

  • a “Range of Uncertainty” and;
  • “Confidence Interval.” 

To illustrate, let’s assume that a blood test result was .100.  Let’s also assume, based on a review of the machine’s prior performance, a “range of uncertainty” was determined to be ± 5%, with a “confidence interval” of 100%.  This means, the reported result could be as low as a .095 and as high as a .105.  Moreover, this also means, if the same blood sample were repeatedly tested on this equipment, the result would only be outside of the ± 5% range 1 out of a million times.  If this statistic were true, this would certainty be a reported result that you could trust.

On the other hand, what if for the same reported result of .100 the range was ± 30%, with a confidence interval of 50%?  Here, this means the reported result could be as low as .070 or as high as .130.   Furthermore, if you continued to test this sample on the same equipment, 300,000 times of out of a million, the reported result would be outside the range stated above.

When comparing the two complete test results, you can see that providing a mere reported result does not tell us the whole story.    Merely telling us the reported result can actually tell us a very misleading story.  Science will not accept incomplete measurements.  Why should the law?