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In a series of posts, I am going to intro­duce the reader to the exis­tence of ISO 17025 and its impor­tance.  I am going to intro­duce it in bite-sized bits for easy diges­tion.  Just like all mat­ters of learn­ing, knowl­edge is incre­men­tal over time and builds upon pre­vi­ous exposure.

In our first post we answered the ques­tion: What is ISO 17025?

The next post we answered the ques­tion: Why do we need stan­dards? Why ISO 17025 and pol­icy, pro­ce­dures and instruc­tions matter.

Then we answered the ques­tion: Why is ISO 17025 so impor­tant to us in foren­sic science?

Just a lit­tle while ago, we asked and answered: Why should the crim­i­nal defense com­mu­nity care about ISO 17025?

Today we exam­ine how ISO 17025 pro­vides a sim­ple method to develop themes to cross-examine experts.

How do you cross-examine an expert?

The above ques­tion I get asked a lot. So much so that I have been invited to speak on the topic before the Texas Crim­i­nal Defense Lawyers Asso­ci­a­tion (TCDLA) at their sem­i­nar enti­tled “Cross Exam­i­na­tion,” which will feature

• Race­horse Haynes
  
• Dick DeGuerin
• Gerry Gold­stein
• Kent Shae­fer
• Terry MacCarthy-  the father of mod­ern cross exam­i­na­tion. Ter­ence Mac­Carthy is syn­ony­mous with effec­tive cross-examination. For 41 years, he has headed the Fed­eral Defender’s Office in Chicago and is among the top CLE instruc­tors in the nation owing to his lec­tures on cross-examination tech­nique. Mac­Carthy is the author of Mac­Carthy on Cross-examination.
• Dan Cogdell-only per­son to gain an acquit­tal in the Enron pros­e­cu­tions
  

As one will dis­cover in our later posts, the spe­cific pro­vi­sions and require­ments of ISO 17025 nat­u­rally gives defense attor­neys  not only great cross-examination themes, but most impor­tantly a prover­bial trea­sure map of the lab­o­ra­tory itself that will allow us to find the nec­es­sary infor­ma­tion to pop­u­late these themes with poten­tially crip­pling infor­ma­tion from the laboratory’s own doc­u­ments and reports.

(Above: a clip from the movie “A Few Good Men”-if you under­stand ISO 17025, you will see if they can han­dle the truth)

ISO 17025 lately has been pre­sented to the crim­i­nal defense field in terms of metrol­ogy. How­ever, it extends past metrol­ogy, and indeed goes into the heart of lab­o­ra­tory sci­ence and the sci­en­tific method itself. If prop­erly under­stood, ISO 17025 pro­vides for sub­stan­tive cross and themes that any defense attor­ney can use to expose crit­i­cal poten­tial issues. These themes include:

• The lim­i­ta­tions of the per­son per­form­ing the test (for exam­ple, the qual­i­fi­ca­tions, the expe­ri­ence and the for­mal knowl­edge of the analyst)
• The cre­den­tials and author­ity of those on the bench and those who super­vise the bench;
• The lim­i­ta­tions of the assays;
• The val­i­da­tion, or lack thereof, of the method;
• The assump­tions made by the method;
• The uncer­tainty in the qual­i­ta­tive result and the Uncer­tainty Mea­sure­ment (UM) in terms of the quan­tifi­ca­tion of the test result; and
• The impor­tance of sam­pling ver­sus sam­ple selection

All of these, it is sug­gested, should be the min­i­mum themes that one uses in cross­ing any prof­fered expert.