Table 1.

Measurements and variables assessed

Type of variable	Variables assessed	Scale or sub-scale	Measures, Author, Year	Number of items	Timeframe
					Entry	After consultation	2 weeks after consultation
1.0 Relationship-centered measures administered in physicians and patients
1.1 Essential elements of SDM (Makoul & Clayman, 2006)
	1.1.1 Knowledge-related Component
	Define/explain problem	Information Giving	Medical Communication Competence Scale, Cegala 1998	9		x
	Present options
	Discuss pros/cons
	Doctor knowledge/recommendations	Doctor recommendations	Patient-Physician Discordance Scale, Sewitch, 2001	7		x
		Perception of the effectiveness of the decision	Decisional Conflict Scale, O'Connor 2005	7		x
	Check/clarify understanding	Information verifying	Medical Communication Competence Scale, Cegala 1998	4		x
		Feeling uninformed	Decisional Conflict Scale, O'Connor 2005	4		x
	1.1.2 Value-related Component
	Patient values/preferences	Values clarification	Decisional Conflict Scale, O'Connor 2005	4		x
		Support	Decisional Conflict Scale, O'Connor 2005	3		x
		Uncertainty	Decisional Conflict Scale, O'Connor 2005	3		x
	Discuss patient ability/self-efficacy	Self-efficacy	Theory of planned behavior	3		x
1.2 Other	1.2.1 Dyadic OPTION	Dyadic OPTION	Dyadic OPTION, Elwyn 2008	12		x
2.0 Patient outcomes
	2.1 Decisional regret	Decisional regret scale	Decisional Regret Scale, Brehault 2003	5			x (patient)
	2.2 Quality of life	Quality of life	Short-form 12, Ware 1996	12			x (patient)
3.0 Characteristics of physicians and patients
	3.1 Attitude towards clinical decisions	Anxiety due to uncertainty	Physician's reaction to uncertainty scales, Gerrity 1995	5	x (physician)
		Reluctance to disclose uncertainty to patients	Physician's reaction to uncertainty scales, Gerrity 1995	5	x (physician)
	3.2 Sociodemographics (physicians and patients)				x (physician)	x (patient)
4.0 Other
	4.1 OPTION third observer	OPTION third observer	OPTION third observer, Elwyn 2001	12		x