Table 1. Psychological measures.

Behaviour	Measure	No. of items	Cronbach's α	Mean (SD)	Median (range)	Percentile (25, 75)	Skewness
Taking a family history	Behavioural intention	3	0.87	6.80 (0.38)	7.0 (5.67–7.0)	6.67, 7.0	−1.88
	Attitude	4	0.54	6.57 (0.46)	6.75 (5.25–7.0)	6.25, 7.0	−0.93
	Subjective norm	4	a	6.38 (0.68)	6.5 (3.5–7.0)	6.0, 7.0	−1.48
	Perceived behavioural control	3	0.52	5.48 (1.1)	5.67 (2.33–7.0)	4.67, 6.33	−0.60
Making a risk assessment	Behavioural intention	3	0.87	4.63 (1.57)	4.67 (1.0–7.0)	3.67, 6.0	−0.49
	Attitude	4	0.91	5.17 (1.35)	5.50 (1.5–7.0)	4.25, 6.25	−0.65
	Subjective norm	4	a	4.79 (1.49)	5.0 (1.0–7.0)	3.75, 6.0	−0.51
	Perceived behavioural control	3	0.66	3.88 (1.21)	4.0 (1.0–7.0)	3.0, 4.67	−0.05
Making a referral decision	Behavioural intention	3	0.85	6.07 (0.93)	6.00 (2.67–7.0)	5.50, 7.0	−1.11
	Attitude	4	0.84	5.99 (0.82)	6.00 (3.75–7.0)	5.50, 6.75	−0.58
	Subjective norm	4	a	5.82 (0.96)	6.00 (3.25–7.0)	5.25, 6.75	−0.60
	Perceived behavioural control	3	0.64	5.04 (1.17)	5.0 (2.0–7.0)	4.30, 6.75	−0.57

^aNot assessed.