Code of Practice

All members of IAFPA are bound by its Code of Practice.  This version of the Code of Practice was approved in September 2020.  [PDF: IAFPA Code of Practice [2020]]

Code of Practice:

The word ‘must’ has been used to indicate a requirement; i.e., members are required to comply with the clause.  

The word ‘should’ has been used to indicate a recommendation; i.e., it is recommended good practice that members comply with the clause

1.         SCOPE

1.1.       This Code of Practice applies to IAFPA members who carry out forensic casework.


2.1.       Members must act in all circumstances with integrity, fairness, and impartiality.

2.2.       Members must be suitably qualified and experienced to carry out the specific type of casework they are undertaking. This may be achieved through a combination of experience, education and method-specific training.

2.3.       Members must maintain and develop their professional competence and knowledge, taking account of research and developments in the relevant fields.

2.4.       Members must maintain awareness of the limits of their competence, and should not carry out casework or provide expert evidence beyond the limits of their competence.

2.5.       When using equipment or software in casework, members must ensure they are adequately trained to use it effectively and appropriately, to recognise erroneous outputs, and to interpret any information obtained.

2.6.       Members should not take on casework where there is a conflict of interest.  In the event that a member becomes aware of a professional or personal conflict of interest after work has begun, they must declare the conflict to the relevant parties immediately.

2.7.       Members must not enter into any arrangements in which remuneration is dependent on the outcome of the case.

2.8.       Members must disclose significant errors in their analysis and / or changes in their opinions to the parties who instructed them, and to the court where applicable, at the earliest possible opportunity.


3.1.       In carrying out their analyses, members should take due account of the available methods and their appropriateness to the samples under examination.

3.2.       Members should take steps to obtain all relevant information regarding the provenance of recordings to be examined, and to ensure that the recordings are as close as possible to the original audio.

3.3.       Members must document the methods they have followed, including details of the hardware and software used, any relevant settings, and any reference data used in forming conclusions. Case notes should be written so that another practitioner can understand them and follow the process carried out.

3.4.       Members should take case-appropriate steps to mitigate the effects of contextual and cognitive bias.

3.5.       Members should, as far as the method allows, test and/or be able to demonstrate the validity (i.e. fitness for purpose) of the methods they employ in casework. Any testing should be carried out using data that is representative of the speech / audio data and conditions encountered in casework.

3.6.       Members should substantiate their professional opinions by referring to background research data and/or literature relevant to the speech and audio conditions encountered in casework, where it is available.

3.7.       For cases that involve evidential interpretation and conclusions, members should consider what the appropriate hypotheses are, and should consider their findings in relation to each hypothesis.

3.8.       It is recommended that members have their analyses and written reports reviewed by a second analyst with relevant expertise.  However, it is acknowledged that this may not be possible in all situations.

3.9.       When carrying out forensic phonetic analysis of speech in a language in which the analyst does not have native-level competence, members should seek assistance from a trained native-level speaker of the language in question.

3.10.   Members should exercise particular caution with cross-language comparisons.

3.11.   Members must not attempt to do psychological profiles or assessments of the truthfulness of speakers.

4.         REPORTING

4.1.       Reports should be written in such a way that the conclusions can be clearly understood by non-specialists, while maintaining scientific accuracy.

4.2.       Where conclusions are presented according to a scale, members should ensure that the range of available conclusions is shown.

4.3.       In order to present a balanced view, members should acknowledge the limitations of their evidence, in reports, in other communications, and when giving evidence in court.