Table 1.

The Eight Key Variables Included in the Scenarios and their Levels

Variable	Levels 1	2	3
1. Orthopnoea	No	Yes
2. Pitting oedema	None	Mild, around ankles	Marked, above knees
3. Ischaemic heart disease	No	Yes
4. Heart rate	60-100	< 60	> 100
5. Lung signs	No crackles	Crackles
6. Chest x-ray (lungs)	Normal	Upper lobe veins enlarged	Alveolar oedema
7. Heart size	Normal	Enlarged
8. Electrocardiogram	Normal	Bundle Branch Block	"Ischaemic"

Key: Scale 1-3 where 1 = normal, and 2 and 3 represent increasing abnormality