Table 1 Recall of trial details.

	HAMLET (n = 28) (n (%))	PAIS (n = 30) (n (%))	p Value
Do you remember your family member having participated in a study?
Yes	23 (82)	21 (77)	0.22
No	5 (18)	9 (30)
What was the treatment under study?*
Correct	24 (86)	12 (40)	0.001
Incorrect	0 (0)	2 (7)
Don't know	4 (14)	16 (53)
What were the presumed effects of the treatment under study?*
Correct	17 (61)	1 (3)	<0.001
Incorrect	5 (18)	10 (33)
Don't know	6 (21)	19 (64)
How was treatment allocation achieved?*
Correct	20 (71)	0 (0)	<0.001
Incorrect	1 (4)	2 (6)
Don't know	7 (25)	28 (94)
Was participation voluntary?
Yes	26 (93)	26 (88)	0.57
No	0 (0)	1 (2)
Don't know	2 (7)	3 (10)
Did you receive written information?
Yes	24 (86)	18 (60)	0.068
No	3 (10)	6 (20)
Don't know	1 (4)	6 (20)
Did you read the written information?*
Yes	21 (75)	12 (40)	0.022
No	2 (7)	3 (10)
Don't know	5 (18)	15 (50)
Did you understand the written information?*
Yes	18 (64)	11 (37)	0.017
No	2 (7)	0 (0)
Don't know	8 (29)	19 (63)

HAMLET, Hemicraniectomy After Middle cerebral artery infarction with Life‐threatening Edema Trial; PAIS, Paracetamol (Acetaminophen) In Stroke trial.

*Statistically significant difference between HAMLET and PAIS.