IAAB Comparative Authentication Framework
(ICAF)
"Many organisations say they are rigorous. Very few explain what makes them rigorous."
Authentication often begins with an observation, a resemblance or an initial impression. The challenge is to ensure that this first impression does not become a conclusion before the available evidence has been properly examined. Expert intuition initiates the examination; structured reasoning determines the conclusion.
The 3 principles behind the framework
“The first plausible explanation is not necessarily the most reliable one.”
“Initial observations are treated as working hypotheses rather than conclusions.”
“Reassessment must be continuous.”
The ICAF Authentication Cycle
The framework is iterative rather than linear. Each stage can lead back to an earlier observation or hypothesis when new evidence emerges.
The ICAF Authentication Cycle Step by Step
1. Observation
The examination begins with what can actually be observed. Observations are recorded without prematurely assigning them a meaning or conclusion. The objective is to distinguish observable facts from their interpretation.
2. Hypothesis
An observation can lead to one or more possible explanations. These explanations are treated as working hypotheses rather than conclusions. Where the available evidence allows different interpretations, more than one hypothesis may need to be considered.
3. Comparison
Each hypothesis is tested against relevant evidence. This may include documented reference works, comparative corpora, documentary records, production characteristics, signatures or other appropriate sources. The relevance and quality of the comparison material must also be considered.
4. Evaluation
The available evidence is assessed according to its evidential weight. Not all characteristics carry the same significance. Their weight must be evaluated in relation to the quality and quantity of the available data, the comparative corpus and the context of the examination.
5. Reassessment
The examination does not end with the first evaluation. New evidence may confirm, weaken or contradict an earlier hypothesis. The examiner therefore returns to previous observations and hypotheses when necessary and reassesses them in light of the evidence as a whole.
At a certain point, a conclusion must be reached based on the evidence available at the time of the examination. That conclusion remains open to reassessment if significant new evidence becomes available.
The strength and reliability of a conclusion may also be influenced by the quality, quantity and evidential relevance of the available evidence, the knowledge available at the time, and the analytical and technological tools available to the examiner.
The Weight of Evidence
Not all observations carry the same evidential weight. A characteristic should not be considered significant simply because it is noticeable or unusual. Its evidential value must be evaluated in relation to the quality and quantity of the available data, the comparative corpus and the context of the examination.
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The weight assigned to a characteristic may also change as the evidence increases. An observation that initially appears significant may become less relevant when a larger and more representative corpus is examined. Conversely, a feature that initially appears minor may become more significant when it repeatedly occurs alongside other independent inconsistencies.
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The ICAF therefore does not treat authentication as a checklist in which every observation carries equal importance. The significance of a characteristic depends on the evidence surrounding it.
Supporting and Contradictory Evidence
Evidence should not be selected only because it supports the initial hypothesis. Evidence that challenges or contradicts that hypothesis must also be identified and evaluated.
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Supporting evidence may strengthen a hypothesis, while contradictory evidence may weaken it, require a different interpretation or lead to a reassessment of the hypothesis itself.
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The ICAF therefore requires both forms of evidence to be considered as part of the same examination. The objective is not to confirm an initial impression, but to determine whether it withstands the available evidence.
The Three IAAB Authentication Pillars
The ICAF builds on three complementary pillars of authentication: Forensic, Documentary and Stylistic analysis. Each examines a different type of evidence, but none is intended to operate in isolation. Their findings are brought together within the ICAF cycle and evaluated according to their relevance, consistency and evidential weight.
A Framework Refined Through Practice
The methodology is not designed first and then simply applied. It is refined through real examinations.
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Each examination can reveal new variables, challenge existing assumptions or demonstrate that a characteristic previously considered relevant has limited evidential value. These findings can refine how future examinations are approached, while preserving the fundamental principles of the framework.
The ICAF therefore evolves through practice, evidence and continuous reassessment.
The Purpose of the ICAF
The ICAF is not designed to eliminate uncertainty or replace professional judgement. It provides a structured framework for managing uncertainty and reducing the risk of human error and cognitive bias during authentication.
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By separating observation from interpretation, testing hypotheses against relevant evidence, weighing characteristics according to their evidential value, and continuously reassessing the findings, the framework seeks to make the authentication process more transparent, consistent and reasoned.
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The objective is not to make authentication infallible. It is to make the reasoning behind an authentication conclusion clearer, more disciplined and open to reassessment when the evidence changes.
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"Rigour is not a claim. It is a process that can be examined."