3. Outcomes: knowledge and understanding (primary).

Primary outcome: knowledge and understanding Knowledge and understanding about what might happen (prognosis), or what to do, or options
Study ID	Information needs	Information preferences	Shared understanding	Timing (longest follow‐up)
Clayton 2007	X Questionnaire; total score out of 11 tallied for items not discussed, items for which they did not receive enough information, or about which they received too much information	X Questionnaire; amount of detail preferred, 1 item, Cassileth Information Styles Questionnaire 5‐point Likert scale	‐	24 hours post‐consultation, 3 weeks post‐consultation
Epstein 2017	‐	‐	X Discordance between prognosis ratings Researcher‐administered questionnaire/interview; 7‐point scale; ‘discordance’ defined as difference of ≥ 2 between category ratings	Shortly after audio‐recorded consultation
Walczak 2017	‐	X Preferences for amount and type of information Self‐administered, Cassileth Information Styles Questionnaire; scores subtracted from baseline preference scores; differences expressed dichotomously (preferences met or exceeded score > 0; unmet < 0)	‐	1 month

X: outcome assessed; ‐: outcome not reported.

The study by Lautrette 2007 reported outcomes related to knowledge (ratings of time allocated for information provision, information clarity, and information seeking by family). As these were assessed at 90 days after the death of the patient, following delivery of a one‐off family conference intervention, we judged that these outcomes were too far removed in time from the intervention to be meaningful. Data were not extracted for analysis from this study, but data are provided in Additional table 9, for transparency.