Table 1

Interviewee demographic characteristics

Identifier	Gender	Age range (years)	Country	Prior participatory experience
Identifier	Gender	Age range (years)	Country	COS development	Delphi survey
P1COS1	Male	65–74	UK	No	No
P2COS1	Female	≥75	UK	No	No
P3COS2	Female	35–44	UK	No	No
P4COS3	Female	Undisclosed	Canada	Yes	Yes
P5COS2	Male	45–54	UK	No	No
P6COS3	Female	55–64	Canada	Yes	Yes
P7COS4	Female	55–64	UK	No	No
P8COS4	Female	55–64	Netherlands	No	No
P9COS5	Female	35–44	Ireland	No	No
P10COS6	Female	45–54	Ireland	Yes*	Yes
P11COS7	Male	55–64	UK	No	No
P12COS7	Female	65–74	UK	No	No
P13COS2	Female	55–64	UK	No	No
HP1COS1	Female	45–54	Canada	No	Yes
HP3COS4	Male	45–54	Spain	Yes	Yes
HP4COS2	Female	35–44	Singapore	Yes	Yes
HP5COS4	Male	35–44	UK	Yes	Yes
HP6COS5	Female	55–64	UK	No†	No
HP7COS5	Female	25–34	Ireland	No‡	No
HP8COS5	Female	35–44	UK	No†	No
HP9COS5	Female	65–74	Ireland	Yes	Yes
HP10COS6	Female	35–44	Italy	No	No
HP11COS6	Male	65–74	UK	Yes	Yes
HP12COS6	Female	55–64	Australia	Yes	Yes

*Interviewee was also the patient research partner of the core outcome set (COS) study they were interviewed in relation to.
†Two health professionals stated awareness/knowledge of COS and Delphi survey but had not participated previously.
‡One health professional was involved in an earlier phase of the COS study for which they participated in the Delphi survey.