Table 2 Common themes, subthemes and quotes identified in response to the question “Can you describe an example of where it had a positive impact?” from “Results” and “Discussion” sections of the questionnaire

Pre award

Helped frame/refine the research question

"The PPI helped frame the clinical question that accompanied my methodological work, in particular the outcomes used and the language used to describe them" (P47)

Emphasised importance of work

"It emphasised the clinical importance of the work and highlighted real life concerns of patients" (P35)

"Contributed for the contextualisation of the problem and to bring to life why it mattered" (P51)

Identified the importance of data quality/linkage

"They reported about the poor quality of their primary care record and encouraged me to use multiple data sources" (P3)

Refined outcomes/language used + direction of project

"It helps shape the methods and choices of variables, as well as giving us grounding in the project" (P45)

"Helped us consider additional potential risk factors/outcomes for our analysis" (P18)

“Guided the scenarios to be considered during a simulation study and terminology being used to describe the methods.” (P79)

Improved application in terms of communicating Plain English Summary

"As a result of the meetings I changed my Plain English Summary so that it was easier to understand from a lay perspective" (P5)

Guided the proposed PPI

"They changed the plans for PPI meetings (if the study was funded) and suggested alternating between in-person and online meetings, having a few static members but cycling through other PPI members to reach a wider and more diverse range of participants. (P23)

Helped guide costings

"Enables us to properly cost the PPIE involvement in the project which funders really liked" (P98)

During project

Improved communication

“Two members also sit on my stakeholder advisory group so they comment on my decisions at key timepoints and help me to determine how to feed this back to participants.” (P46)

Helped frame/refine the research question

“Working with care-experienced children was very important and meaningful. Understanding their opinions on what care placements were the most important, along with the key risk factors for education allowed us to think about how we could streamline our analysis” (P68)

Provided input into modelling

“Suggested an alternative modelling strategy” (P104)

“Asked for and gained input on design of prediction model tool” (P109)

Refined materials/tools used

“PPI help to design trial information material” (P52)

“Improved language used for web-based tool” (P62)

Provided the bigger picture and clinical perspective

“Forced methodologists to think about the bigger picture” (P33)

“Added balance to clinical views and different perspectives” (P100)

“They have always been great at reiterating why the work is important from their perspective which gives a sense of purpose to the projects” (P51)