Quality Control of Forensic Evidence

When an item of evidence that could be crucial to securing a conviction appears in court, judge and jury want to be sure that it really is relevant to the crime. The only way of fulfilling this requirement is to make the concept of quality central to everything the forensic investigator does with the evidence, from collecting it to presenting it in court. This striving for quality is not confined to forensic science ; it is found in most other industries, from pharmaceuticals to aerospace. The underlying goal is to offer products and services to the public that are safe and effective. In forensic science, quality of evidence is important because if first-rate evidence is not submitted in court, the guilty may go unpunished or, equally, an innocent person may lose their liberty.

The terms quality control (QC), and quality assurance (QA) are often used interchangeably. What is more, their meanings may differ from place to place and between different kinds of activity. Put simply, QC covers all the different activities done to fulfill quality requirements for a product or service. In forensic science, this might cover the need to run control samples when doing a DNA analysis or to keep records of exactly what was done in the microscopic examination of a hair sample. The term QA is a broader one, covering the overall system of dealing with evidence and includes issues such as staff training and qualifications and the laboratory environment. A disorganized laboratory, with no clear chain of command, cannot reasonably be said to be providing good QA. In this article, the term QA/QC will be used to cover all aspects of quality in forensic investigation.

The idea of quality began with medieval craftsman who organized themselves into guilds dedicated to making products of a high standard. Products that reached the quality standards of an inspecting committee would receive a special quality mark. Master craftsmen began to add their own quality marks to their products to guard their reputation and standards. Customers who bought products bearing inspection and master craftsman marks were assured of the quality of their purchase. It was in the twentieth century that the concept of quality was broadened to include many more products and services, including forensic science. The medieval quality marks have evolved into a more general idea of standards, which are procedures, metrics (measurements), behaviors, or whatever is needed in a particular activity to guarantee a quality output.

Standards vary from place to place, so there is a need for some kind of international reference. After all, the result of DNA identification should not vary depending on the country or laboratory where it was done. If the defense orders a second opinion, then it merely confuses matters if the second lab follows a different procedure from the first one. The ISO (International Organization for Standardization) 9000 series is a set of international standards on quality management and QA/QC, which was established in 1987 and is constantly being updated and revised. A lab dedicated to forensic investigation can be registered to ISO 9000 standard, which gives proof of the quality of its work. Another important idea in the improvement of quality is benchmarking. This involves a search for a benchmark, an example of best practice or the best way of doing something, and comparing current practice with the benchmark. Quality is an evolving concept, with organizations and individuals continually being challenged to reach ever-higher standards. In science, methods and equipment are changing all the time, and laboratories and their personnel must keep up and adapt. For crime investigation, this can only be a good thing, for it means enhancing the court's confidence in the evidence being presented.

In the context of forensic investigation, QC/QA covers scientific, legal, and ethical aspects of the work of both laboratory scientists and the police scene-of-crime officers. Forensic science involves many different disciplines, from pathology and chemistry to engineering and entomology . Whatever the nature of the evidence, however, its preservation from deterioration or contamination is paramount. Trace evidence , in particular, is vulnerable in this respect. Protective clothing at the scene and restricted access can help preserve the evidence that is present. After that, proper and securing packaging is essential. Once in the laboratory, the evidence must be correctly stored, which may involve refrigeration or protection from moisture, and it must never be left unattended or unsecured in case of tampering or theft.

When it comes to laboratory investigation of the evidence, there will be Standard Operating Procedures (SOPs) and Standard Methods (SMs) that must be followed. These are written instructions as to how to carry out a given task using properly tried and tested methods. These SOPs and SMs will change over time, as new methods, equipment. and evidence emerge. A court would, rightly, not be impressed to discover that a forensic laboratory was still carrying out, for example, fingerprint analyses according to a method from the 1950s.

A wide range of equipment, including spectrometers, microscopes , cameras , and gas chromatographs is used in the forensic laboratory. An important part of QA/QC is ensuring all this equipment is properly used by staff that have received correct training. The equipment must also be properly and regularly calibrated, that is, run with reference samples to ensure its correct operation. It must also be regularly maintained and replaced or upgraded if faults occur.

Quality standards apply as much, if not more, to the people working in the forensic laboratory as to the equipment and methods they use. First, the person must have the appropriate scientific qualifications for the job. Requirements may vary, but each person should have a written job description including their responsibilities, duties, and skills required. The manager of the laboratory will have had several years of experience of forensic work. Technicians will have qualifications appropriate to the type of work they are carrying out. Everyone's work needs to be supervised and audited, both internally and externally. Because forensic science is such a rapidly evolving discipline, it is essential that there be provision for continuing education for everyone employed in the laboratory. This might include the opportunity to take a higher degree and will certainly involve taking courses to learn new techniques from time to time and keeping up with the professional literature to increase awareness of developments. In addition, an important part of being a forensic science professional is to be prepared to testify in court. This may involve fierce cross-examination and the individual must be objective and confident enough to defend their work as well as making the principles and detail involved accessible to the judge and jury.

Everyone working in a forensic laboratory must do all they can to take a scientific, objective, approach to their work, just as one would in any other laboratory setting. This means being unbiased, prepared to repeat experiments, using control and reference samples, and keeping accurate records of procedures carried out and results obtained. Over and above this, there are special requirements for forensic investigators relating to ethical and legal aspects of the work. Perhaps the most important requirement here is an awareness of the importance of the chain of custody of evidence. This means that it must be clear to the court exactly what has happened to the evidence from the moment of its collection to its presentation in the courtroom. Everyone who handled the evidence in any way must sign for it and record what they did with it. Only with an unbroken chain of evidence can the judge and jury be sure of the relevance of the evidence to the crime under investigation.

Not only must the evidence itself be properly handled and accounted for at all times, careful records must also be kept of all operations carried out on it. At one time, these would have been hand written. Now, however, there are many computerized laboratory information handling systems. The forensic laboratory should be using a recognized and acceptable system and all personnel should be trained in its correct use.

People who choose to work in forensic science generally do so because they have a keen interest in the subject and are motivated to help solve crimes and see justice done. However, it is not unknown for a forensic investigator, maybe under the stress of his or her workload or maybe for more sinister reasons, to lose or destroy evidence, make mistakes, or even to falsify results. The QA/QC system should allow for the rapid detection and correction of this kind of incident.

Laboratories doing forensic work can apply for accreditation by an independent third party, which is also seen as an important part of QA/QC. In the United States, this accreditation is carried out by the American Society of Crime Laboratory Directors through their Laboratory Accreditation Board. A satisfactory evaluation and on-site inspection of the organization, staffing, and facilities of a laboratory can lead to accreditation. After this, a full re-inspection will be carried out every five years. Many laboratories in the United States have been accredited in this way and similar schemes apply in other parts of the world, such as the United Kingdom. Forensic science cannot stand still when it comes to quality; the discipline must always be striving to improve.

see also Disturbed evidence; Evidence.