Category Archives: PCAST Report

National Forensic College 2018 announced

The 5th annual NACDL and Cardozo School of Law National Forensic College (NFC), presented in collaboration with the Administrative Office of the U.S. Courts, Defender Services Training Division, will take place Sunday, June 3 through Friday, June 8, 2018 in New York City.

The goal of the college is to train experienced litigators in state and federal defender offices, both trial and post-conviction, to litigate complex forensic science issues strategically and with the support of the nation’s leading law firms and experts. Afterwards, attendees are expected to train legal professionals in their jurisdictions in these areas and work with fellow lawyers to develop successful litigation strategies to address forensic issues.

Topics for 2018 will include: False Confessions, Pattern Evidence, Digital Evidence, DNA (including an advanced track), Eyewitness Identification, Toxicology, plus instruction on statistics in forensics and an update on ligation using the PCAST report.

Attendance is by invitation only, but private attorneys can apply to attend. The cost to attend for private attorneys is $999 for the week, plus the cost of housing. The application and additional information is available here.

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Judging Forensics

Federal district judge for the Southern District of New York Jed S. Rakoff delivered the keynote address, “Judging Forensics” during the Forensics, Statistics and Law conference at the University of Virginia School of Law on March 26, 2018. The address can be viewed online here.

Judge Rakoff’s presentation commemorated the 25th anniversary of the U.S. Supreme Court’s decision in Daubert v. Merrell Dow Pharmaceuticals Inc. which reshaped how judges evaluate scientific and expert evidence. The presentation looked at how courts have considered the admissibility of testimony about scientific evidence and specifically forensic evidence. Judge Rakoff cited a study which found that in Daubert challenges between 1993 and 2001, defense proffers of expert testimony were rejected 92 percent of the time, whereas where the prosecution was the proponent of the evidence, expert testimony was admitted 95 percent of the time. Judge Rakoff examined some reasons for that disparity.

He addressed the NAS Report and PCAST Report and several examples of unreliable forensic science and statistical evidence, including a hair comparison case and a case where a mathematics professor improperly calculated the likelihood of a two suspects driving a specific car and was allowed to testify to that evidence. The question and answer session offered important insights into how these issues can be addressed.

Recordings of additional presentations and panels are available on the UVA Law YouTube channel (scroll down to “uploads”) or here. Attorneys may be interested in viewing Dr. Peter Stout’s presentation on the use of blinds at the Houston Forensic Science Center (at 27:50), Henry Swofford’s presentation on the use of statistical software in fingerprint comparisons at the Defense Forensic Science Center (at 1:12), and Dr. Alicia Carriquiry’s presentation on statistics and the evaluation of forensic evidence.

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New Benchbook Chapter on Expert Testimony

School of Government Professor Jessie Smith has drafted a new chapter on Expert Testimony for the NC Superior Court Judge’s Benchbook. I’ve already heard one judge say from the bench that he had it open as he was considering a 702 challenge to expert testimony. Because this is a resource that judges look to, defenders should be familiar with it when preparing for 702/Daubert hearings regarding expert testimony.

Professor Smith references the President’s Council of Advisors on Science and Technology report, Forensic Science in the Courts: Ensuring Scientific Validity of Feature Comparison Methods, (hereinafter, PCAST Report) (available for free download here). The chapter uses the PCAST Report and other resources to note areas where there are questions about the reliability of certain types of forensic evidence. I have posted about the 2016 PCAST Report here, and I hope its being referenced in the Benchbook will lead to judges and other court actors taking a look at that landmark report on forensic evidence.

A significant portion of the chapter looks at each type of forensic evidence and summarizes the existing case law and mentions additional relevant considerations. Other sections of the chapter that defenders will want to take note of are the section on statements and terminology that the PCAST Report says are not scientifically valid (p. 54), the section on whether judges declaring a witness to be an expert in the presence of the jury inadvertently puts the court’s stamp of authority on a witness’s opinion (p. 22), and the discussion on best practices regarding the procedure for holding a 702/Daubert hearing (p. 21-22).

 

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Using the PCAST Report in the Courtroom

The President’s Council of Advisors on Science and Technology (PCAST) report on Forensic Science in Criminal Courts: Ensuring Scientific Validity of Feature-Comparison Methods was released on September 20, 2016. (Available for free download here.) The PCAST report gives an in-depth look at the current state of certain forensic science disciplines. It makes recommendations as to the use of forensic science evidence in court, improvements to be made in research and improvements to be made in forensic science in general. This report will be very useful in the courtroom, as it uses a framework to assess scientific validity that mirrors the NC Rule of Evidence 702, which governs the admissibility of expert testimony.

The report evaluates whether eight areas of forensic evidence are foundationally valid and validly applied, which are equivalent to prongs two and three of Rule 702 (whether the testimony is the product of reliable principles and methods (prong 2) and whether the witness has applied the principles and methods reliably to the facts of the case (prong 3)).

The summary for each discipline examined is as follows:

  • DNA analysis of single-source and simple-mixture samples: Foundationally valid, but examiners should undergo rigorous and relevant proficiency testing, should routinely disclose in reports and testimony whether he or she was exposed to any facts of the case that might have influenced the conclusion, and should disclose upon request all information about quality testing and issues in the lab.
  • DNA analysis of complex-mixture samples: Objective analysis based on probabilistic genotyping is new but promising; more research by independent scientists pertaining to accuracy in different scenarios is needed. Some methods may be valid for use in certain situations (e.g., an adequate sample with up to 3 sources and at least a 20% contribution of the smallest contributor).
  • Bite mark analysis: Bite mark analysis as used to identify a source of a bite mark or to establish whether an injury is due to a human bite mark is scientifically unreliable, and additional research in this area is not warranted as it is unlikely to be developed into a reliable and accurate methodology.
  • Latent print analysis: Has a foundationally valid subjective methodology, but the false-positive rate is substantial and likely to be higher than expected by many jurors. Conclusions need to be accompanied by accurate information about reliability and false positive rates. Several steps should be taken to further strengthen latent finger print analysis, including blinded proficiency testing incorporated into regular casework, limiting an examiner’s access to potentially biasing information and applying a “linear” analysis (examining and documenting features of the unknown sample before comparing them to a known sample). All of these factors should be considered when determining whether the techniques were validly applied in the case at hand.
  • Firearms analysis: PCAST concluded that the foundational validity of firearm analysis had not been established: only one study was found that examined accuracy and reliability (and that met the criteria for how such a study should be designed and conducted). The false positive rate was 1 in 66 examinations (upper 95th percentile confidence limit 1 in 46 cases). PCAST recommended additional studies using representative samples to establish accuracy and the creation of databases to establish prevalence of features.
  • Footwear analysis: Foundational validity has not been established, as no properly designed empirical studies to evaluate accuracy in associating a shoe print to a specific shoe have been conducted. Additional research should also include creation of databases to establish prevalence of features.

The PCAST report did not do a comprehensive evaluation of microscopic hair analysis, but did review the Department of Justice’s (DOJ) recently released proposed Uniform Language for Testimony and Reports, and its Supporting Documentation, for this discipline. PCAST noted that DOJ’s statement that “microscopic hair comparison has been demonstrated to be a valid and reliable scientific methodology” is not supported by the available studies. The report specifically noted an FBI study from 2002 comparing microscopic hair analysis to DNA analysis in 170 samples, in which a false positive rate of 11% was found.

The PCAST report also gives suggestions as to how to improve research in forensics fields. To this end, it calls upon the National Institute of Standards and Technologies to take on the task of determining if new and current fields are foundationally valid as defined by the document. It also recommends that more unaffiliated scientists be consulted by the Organization of Scientific Area Committees. The report calls for the creation of a Metrology Resource Committee which it suggests be made up of independent scientists. This committee would review the OSAC’s standards with an eye towards their reliability and validity.

Also included in the report are suggestions for improving the use of forensic evidence in court. The report calls on the U.S. Attorney General to direct attorneys appearing on behalf of the USDOJ to ensure expert testimony meets the standards for scientific validity (p. 140-141). Furthermore, it provides guidance to judges in determining the scientific validity as a foundation for expert testimony. The report suggests that judges review false positive rates, the method’s sensitivity, the sufficiency of validation studies, the appropriateness of proficiency testing, adequacy of procedures used and documentation and whether appropriate limits on reporting language were employed. It also recommends that best practices materials and training on scientific evidence be made available for judges (p. 145).

The PCAST report also recommends that for each field, the proponent of the forensic evidence

  • Demonstrate the capability of the analyst through routine, blinded proficiency testing.
  • Demonstrate that the techniques were reliably applied in the case by providing a complete description of the procedures, results and laboratory notes.
  • Utilize comprehensive and accurate reporting and testimony, including information from the empirical studies of false positive rates and sensitivity, information on the comparability between the types of samples used in these empirical studies and the sample(s) available in the particular case, and an accurate portrayal of the probative value of the observed features (i.e., how common or rare the features are, based on empirical studies).

This report will be useful for attorneys considering a challenge to testimony by forensic experts, as it explains in an accessible way what must be shown to demonstrate reliable principles and methods and reliable application of those principles and methods in a particular case. It is a worthwhile read for every criminal advocate as it suggests a framework for making a rigorous challenge to the admissibility of expert testimony.

The National Association for Public Defense is offering a webinar entitled, Denuding the Emperor: Understanding and Using the PCAST Forensic Science Report at 1:00 pm on Dec. 2, 2016.  Andrew Northrup, Assistant Public Defender in the Maryland Office of the Public Defender will discuss how the PCAST report can be used in the courtroom. The program is free of charge for NAPD members and $20 for non-members.

I would like to thank Glinda Cooper, Director of Science and Research for the Innocence Project for her contribution to this post.

 

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