The Role of Professional Judgment ISO/IEC 17020 for Crime Scene & Digital Forensics

Forensic Advantage
Jul 2
4 min read

Explore the role of professional judgment in ISO/IEC 17020 for crime scene & digital forensics and how FA OnScene can help.

Crime scene investigation, digital forensics, and comparative disciplines such as latent prints and firearms & toolmarks are built on more than just data; they depend on the professional judgment of trained examiners making critical decisions in real time. Whether choosing the correct reagent for developing a latent print, selecting the most effective chemical for serial number restoration, or determining the proper technique for documenting a complex scene, these disciplines require expert interpretation that can’t be reduced to a standard checklist.

Because of this, ISO/IEC 17020 is the preferred accreditation standard for these types of forensic inspections. It’s specifically designed to support disciplines that rely on evaluative decisions and subjective assessments, ensuring processes are defensible, consistent, and rooted in expert knowledge.

In the latest installment of our forensic accreditation series with A2LA, we take a closer look at how ISO/IEC 17020 supports these specialized disciplines and how tools like FA OnScene help investigators and examiners document and manage their work with precision, accuracy, and accountability.

Why ISO/IEC 17020 is Ideal for Crime Scene, Digital, and Comparative Forensics

While ISO/IEC 17025 is commonly used for laboratory-based testing disciplines (such as toxicology or controlled substances), it may not fully address the needs of fields like crime scene investigation (CSI), digital forensics, or comparative disciplines like latent prints and firearms & toolmarks. These forensic disciplines are inspection-based, requiring interpretative skills, on-scene evaluations, and dynamic decision-making based on the unique conditions of each case.

ISO/IEC 17020 was developed to promote confidence in inspection bodies by ensuring that they meet requirements for competence, impartiality, and consistent operation. It emphasizes professional judgment in real-time scenarios, like choosing the correct chemical for a bloody latent print, selecting the proper reagent for serial number restoration, or determining the sequence of digital evidence extraction.

Key characteristics of these disciplines:

There are multiple valid approaches to data interpretation, scene documentation, or evidence handling.
The work involves a blend of technical expertise and situational judgment, rather than purely analytical measurements.
Choosing the wrong reagent or method could permanently alter or destroy critical evidence, making judgment and training essential.

Disciplines that benefit from ISO/IEC 17020 include:

Crime Scene Investigation – Scene documentation, evidence collection, shooting reconstruction, bloodstain pattern analysis, and more.
Digital Forensics – Device seizures, data imaging, digital evidence preservation, file reconstruction, and video/audio analysis.
Latent Prints & Firearms/Toolmarks – Where expert judgment informs method selection based on surface type, material composition, or case context.

The Importance of Professional Judgment and Ongoing Training

Unlike testing disciplines, which produce results based on measurable, repeatable inputs, inspection-based disciplines demand real-time professional interpretation. Success hinges on an inspector’s ability to evaluate variables, select the appropriate process, and defend their conclusions with confidence.

ISO/IEC 17020 emphasizes:

Competence - Inspectors must demonstrate advanced knowledge, discipline-specific skills, and the ability to apply judgment appropriately.
Training & Continuing Education - Conformity Assessment Bodies (CABs) must provide structured initial and ongoing training to ensure inspectors stay current on evolving tools, methods, and regulations.
Witnessed Inspection Evaluations - Periodic evaluations ensure each inspector can perform under real or simulated conditions, maintaining quality and defensibility.
Documentation of Professional Judgment - All conclusions must be documented clearly and accurately, including justification for decisions made during the inspection.

These requirements ensure consistency, help mitigate human error, and reinforce courtroom defensibility. They also promote the development of well-rounded forensic professionals equipped to handle the unpredictability of crime scenes and digital evidence.

How FA OnScene Supports ISO/IEC 17020 Compliance

Forensic Advantage’s FA OnScene is a digital inspection tool that helps CABs meet ISO/IEC 17020 requirements with precision and consistency. Whether you're managing crime scene documentation or digital forensics activities, FA OnScene offers robust tools to maintain quality and transparency in the field.

Key features include:

Field-Based Documentation: Collect, document, and annotate evidence in real-time, with built-in prompts that guide consistent data entry.
Lab Resource Management: Built-in resource management ensures that only properly maintained equipment, chemicals, etc. are available for use.
Professional Judgment Support: Log decisions and interpretations clearly, with audit-ready records that back up expert assessments.
Technical and Administrative: review built in where and when you
Secure Data Sync: Automatically sync data to your LIMS system for continuity, secure storage, and easy retrieval.
Role-Based Authorization: Roles and Authorization are controlled by you based on your SOPs. Protect sensitive data while allowing authorized parties, such as supervisors or QA staff, to review entries for compliance.
Custom Workflows: Tailor the platform to your CAB’s SOPs, jurisdictional needs, or accreditation requirements.
Batch Processing: Bi-directional communication between LIMS and instrument equipment speeds processing and ensures auditable data integrity.
FA OnScene: bridge the gap between the lab and the field, ensuring compliance without sacrificing the flexibility of starting a case and recording crime scene details in the field.

Final Thoughts

Accreditation under ISO/IEC 17020 helps ensure that the activities conducted by the inspection bodies include matters of quality, safety, and fitness of purpose. In the forensic fields where evidence is often subjective, interpretations vary, and scenes evolve rapidly, a strong accreditation foundation reinforces public trust, strengthens courtroom testimony, and modernizes operations across the organization.

In combination with the appropriate standard with the latest technology, forensic CABs can enhance both their credibility and efficiency.

This is Part 4 of our Forensic Accreditation Series with A2LA. Like and follow our LinkedIn pages as we continue to explore the path to accreditation success for forensic organizations and catch up on what you missed. For more information, read the white paper authored by Brittney Rollison, Senior Accreditation Officer at A2LA.