When anonymising qualitative material - such as transcribed interviews, textual or audio-visual data - pseudonyms or vaguer descriptors should be used to deal with any problematic identifying information. Obtaining informed consent for data sharing or regulating access to data should also be considered alongside any anonymisation.

When anonymising qualitative data, consideration should be given to the level of anonymity required to meet the needs agreed during the informed consent process. Researchers should not presume the only way to maintain confidentiality is by keeping data hidden.

Pre-planning and agreeing with participants during the consent process, on what may and may not be recorded or transcribed, can be a much more effective way of creating data that accurately represent the research process and the contribution of participants.  For example, if an employer's name cannot be disclosed, it should be agreed in advance that it will not be mentioned during an interview. This is easier than spending time later removing it from a recording or transcript.

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Often researchers presume that participants want their data destroyed or kept confidential and inaccessible. However, they might be quite willing to have their data shared with other researchers if appropriate pseudonyms and other protections are provided.

If you need to anonymise textual data, information should not simply be removed or blanked-out. Pseudonyms, replacement terms, vaguer descriptors or systems of coding should be used to retain maximum content. Best practices for anonymisation of text are:

• do not collect disclosive data unless this is necessary, e.g. do not ask for full names if they cannot be used in the data
• plan anonymisation at the time of transcription or initial write up, except for longitudinal studies where relationships between materials may require special attention during editing READ MORE ABOUT TRANSCRIBING DATA
• use pseudonyms or replacements that are consistent within the research team and throughout the project, e.g. use the same pseudonyms in publications or follow-up research
• use 'search and replace' techniques carefully so that unintended changes are not made, and mis-spelled words are not missed
• identify replacements in text clearly, e.g. with [brackets] or using XML tags such as <seg>word to be anonymised</seg>
• retain unedited versions of data for use within the research team and for preservation
• create an anonymisation log of all replacements, aggregations or removals made - store such a log separately from the anonymised data files

example anonymisation log:

anonymisation example:

In an interview transcript a person's name is replaced with a pseudonym or with a tag that typifies the person [farmer Bob, paternal grandmother, council employee]. This is also done when reference is made to other identifiable people. An exact geographical location may be replaced with a meaningful descriptive term that typifies the location [southern part of town, near the local river, a moorland farm, his native village].

For anonymising audio-visual data such as digital images or audio recordings, digital editing to remove identifying detail should be done sensitively.  Bleeping out names or place names is acceptable, but disguising voices by altering the pitch in a recording, or obscuring faces by pixellating sections of a video image significantly reduces the usefulness of data. These processes are also highly labour intensive and expensive.

If confidentiality of audio-visual data is an issue, it is better to obtain the participant's consent to use and share the data unaltered.

Where anonymisation would result in too much loss of data content, regulating access to data can be considered as an effective strategy.

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We urge researchers to consider and judge at an early stage the implications of depositing materials containing confidential information and to discuss any issues with us. Call us on +44 (0)1206 872974 or email us