Table 2.

Outcomes and outcome measures of ACP+ trial

Outcome	Respondent	No. of items	Item example(s)
Knowledge of ACP	Nursing home care staff (primary outcome)	11 items*	“A resident can only assign a family member as his/her legal representative”
Self-efficacy towards ACP	Nursing home care staff (primary outcome)	12 items†	“Point out how much confidence you have in your own skills with regard to the following activities/roles: To explain the role of a legal representative to residents and family”
	Support staff	3 items†	“Point out how much confidence you have in your own skills with regard to the following activities/roles: To talk about wishes regarding future care with family members and residents”
	Volunteer	3 items†	Same as above
Attitudes towards ACP	Nursing home care staff	12 items‡	“GPs should be involved actively to help residents draft an advance directive”
ACP practices	Nursing home care staff	8 items	“Did you start an ACP conversation the past six months?”
	Support staff	2 items	E.g. 1: “In the past six months, did you talk with a resident about the next themes: future care and his/her related wishes, dying and death, advance directives?” E.g. 2: “In the past six months, did you talk with a family member or next-of-kin of a residents, about the next themes: future care and his/her related wishes, dying and death, advance directives?”
	Volunteer	2 items	Same as above
Demographic and background information	Nursing home care staff		Age, gender, date of today, number of years working experience in direct patient care, number of years employment in nursing home sector, current function in the facility, highest education, number of hours working in the nursing home per week, whether or not they received training in palliative care or ACP, average number of residents for which they care on regular working day.
	Support staff		Age, gender, date of today, number of years working experience in direct patient care, number of years employment in nursing home sector, current function in the facility, highest education, number of hours working in the nursing home per week, whether they received training regarding one of the following themes: vision and values of the nursing home, palliative care, communication skills, information transfer about resident to other care staff, ACP, other; if they had a personal conversation with a resident that has dementia or Alzheimer’s.
	Volunteer	7 items	Age, gender, date of today, employment status, highest education, number of years active as volunteer, number of years active as volunteer in this nursing home
Structural facility-level characteristics	Key contact person in nursing home	21 items	Type of facility, number of beds recognized by government, number of beds available, number of beds occupied, number of residents per KATZ scale category, umbrella organisation, with which electronic resident file system they work (e.g. GERACC, Care Solutions or others), number of residents died over past six months, average time of stay, availability of specific written guidelines available about palliative care or ACP, availability of patient-specific forms regarding ACP, % of residents died in nursing home, % of residents that has an up-to-date plan regarding end-of-life care, number of residents with written AD, regular multidisciplinary team meetings, number of staff: FTE and heads, number of volunteers registered in nursing home, number of hours per week the coordinating advisory physician is present in facility, number of GPs involved with patients in nursing home

ACP advance care planning; GP general practitioner; FTE full-time equivalent; AD advance directive; KATZ index of independence in activities in daily living; GERACC software package for nursing homes in Belgium

*Response categories: ‘True’, ‘False’ or ‘I don’t know’

†Response categories: 10-point Likert scale, ranging from ‘little confidence’ (=0) to ‘a lot of confidence’ (=10) and ‘not applicable’

‡Response categories: 5-point Likert scale ranging from ‘Completely disagree’ (=0) to ‘Completely agree’ (=5)

§Response categories: ‘Yes’ or ‘No’