ISO 21043-4 — Forensic sciences — Part 4: Interpretation
International Organization for Standardization · Edition 1, published 2025-06 · 2025
Identifier: ISO 21043-4:2025
Access and status
Cost
Paywalled
Behind a subscription or per-item charge. Check whether your firm, university or public library already has access before paying at the door.
Status
Current
Current as at the verification date below. Standards and tools both move — confirm at source before you rely on it.
What it is
A 14-page international standard on the interpretation of forensic findings, published in June 2025 as part of the ISO 21043 forensic sciences series. Parts 1 (vocabulary, 2025), 3 (analysis, 2025) and 5 (reporting, 2025) are also published; part 2 is being revised, with ISO/DIS 21043-2 at DIS stage as at September 2026.
Who it is for, and when
Read it if you give opinion evidence. It is the first ISO-level statement of requirements for how findings are evaluated against competing propositions, and it is discipline-neutral, so it applies to digital evidence as much as to DNA. Expect opposing experts and regulators to start citing it. It is paywalled: iso.org listed it at CHF 100 in September 2026, and readers should check iso.org for a newer revision before relying on this edition.
What it does not cover
It is a requirements document, not a tutorial: it will not teach you Bayesian reasoning or likelihood ratios, and it contains no digital-forensics worked examples. For those, the ENFSI evaluative reporting guideline is the practical companion.
Go to the source
Open at iso.org (opens in a new tab)https://www.iso.org/standard/72039.html
Details
- Type
- Standard or guidance
- Written for
- Working examinerLawyers and courtsAdvancedWorking examiner, Lawyers and courts, Advanced
- Publisher
- International Organization for Standardization
- Version verified
- Edition 1, published 2025-06
- Year
- 2025
- Identifier
- ISO 21043-4:2025
- Topics
- interpretation, evaluative-reporting, expert-testimony, standards-development
- Checked at source
- Standards are revised. Confirm the current revision with the publisher before citing this.
Related entries
The output of ENFSI's STEOFRAE project (Strengthening the Evaluation of Forensic Results across Europe): a guideline on evaluating findings against competing propositions and reporting the strength of that evaluation, with an audit template, an implementation roadmap and nine worked case examples.
A 10-page international standard specifying requirements for forensic reports and for the communication of findings, published June 2025 as part of the ISO 21043 series.
Standardization of forming and expressing preliminary evaluative opinions on digital evidence
PaywalledEoghan Casey's paper in Forensic Science International: Digital Investigation on how digital forensic practitioners should form and state evaluative opinions, importing the strength-of-evidence reasoning used elsewhere in forensic science into digital evidence and proposing a standardised scale for preliminary opinions.
The congressionally requested report that found much of US forensic practice lacked demonstrated validity, consistent standards, and independence from law enforcement, and recommended a national institute to set and enforce them. It reset how courts and commentators talk about forensic reliability.
A 14-page standard that picks up where ISO/IEC 27037 stops, covering the analysis and interpretation of potential digital evidence and the competence and proportionality considerations that go with them.