Public involvement -the process by which research is conducted in collaboration with patients, carers or members of the public -is increasingly considered a prerequisite for high-quality research. 1 Evidence suggests that public involvement can benefit research by helping to identify and prioritise patient-focused research questions, aiding recruitment and retention, and helping to foster greater links between researchers and the wider community. [2][3][4] Public involvement is encouraged across the research cycle and guidance has been developed to support researchers to involve the public at each stage. 5,6 However, currently, such guidance is focused on studies which include primary data collection, and there is little guidance on how to meaningfully involve the public in big data research.Big data research takes many forms. 7,8 In palliative care, this research often involves secondary analysis of routinely collected data (i.e. data initially collected for other purposes other than research, as part of a standard administrative or care process) such as death registry data and electronic health records. 9,10 Differences in the reported presence of public involvement across studies have shown that involvement in big data research is significantly limited in comparison with other study designs. 11 It has been suggested that this may be because common approaches to public involvement adopted in primary data research are not appropriate within big data analysis studies. 12,13 While public members are commonly involved in primary research to review and develop patient information leaflets or other research materials, undertake interviews with research participants or even support recruitment for a clinical trial, these involvement opportunities are not applicable to big data research. 13,14 In addition, the highly data driven discussions that underline this type of research can present a barrier to public involvement with 'unfamiliar' and 'scientific' language repeatedly being cited as an obstacle, across fields. 15 Due to this there is now growing recognition that public involvement in big data research requires special considerations. 13