Table 2.

Properties of the psychological construct scales.

Construct	Example item	Interitem correlation at baseline				Paper adapted from
		Correlation coefficient (Rs)	n	P value
Action self-efficacy	“I am confident that I can take my diabetes tablets as prescribed”	0.82	203	<.001		Schwarzer et al [25]
Necessity	“My health in the future will depend on my diabetes tablets”	0.53	203		<.001	Horne et al [26]
Concerns	“I sometimes worry about the long-term effects of my diabetes tablets”	0.19	203		.007	Horne et al [26]
Intention	“I will take my diabetes tablets as prescribed every day over the next 3 months”	0.81	204		<.001	Presseau et al [27]
Automaticity	“Taking my diabetes tablets as prescribed is something I do without thinking”	0.50	199		<.001	Gardner et al [28]
Maintenance self-efficacy	“I am confident that I am able to take my diabetes tablets as prescribed even when something disrupts my routine”	0.54	200		<.001	Greer et al [29]
Recovery self-efficacy	“If I don’t take my diabetes tablets for any reason, I am confident that I am able to start taking them again even if I feel no different to when I was not taking them”	0.63	201		<.001	Greer et al [29]
Action planning	“I have made a detailed plan about exactly where to take my diabetes tablets”	0.72	200		<.001	Greer et al [29]
Coping planning	“I have made a detailed plan for how to deal with unpleasant side effects of taking my diabetes tablets as prescribed”	0.46	200		<.001	Greer et al [29]
Action control	“During the last 4 weeks I consistently monitored when, where, and how I took my diabetes tablets”	0.23	201		.001	Sniehotta et al [30]
Prompts and cues	“I use things around me to help me to take my diabetes tablets as prescribed (e.g. notes, phone reminders)”	0.63	202		<.001	N/Aa
Social support	“I have felt supported in taking my diabetes tablets as prescribed”	0.29	202		<.001	Presseau et al [27]
Satisfaction with experienced consequences	“I am content with what I have experienced as a result of taking my diabetes tablets”	0.75	203		<.001	Baldwin et al [31]
Risk perception	“I feel very at risk of developing complications, or experiencing worsening of existing complications from my diabetes if I do not take my tablets”	0.64	201		<.001	N/A

^aN/A: not applicable.