Table 1.

Survey measures to be completed by participants at baseline (approximately 3 weeks post-donation) and after telephone contact (approximately 7 weeks post-donation).

Measure	Description	Sample item	Response Anchors
Blood donor identity Survey	An 18-item measure of six different regulatory styles, ranging from unmotivated to donate to increasing levels of autonomous motivation to donate (i.e., non-regulation to intrinsic regulation).	“Donating blood is consistent with my life goals.”	(1) Not at all true to (7) Very true
Blood donation attitude	A 6-item measure of attitudes towards blood donation that yields a total score as well as subscale scores cognitive attitude (evaluative judgments) and affective attitude (emotional reactions).	“For me, donating blood within the next 8 weeks would be…”	(1) Unpleasant to (7) Pleasant
Blood donation subjective norm	A 6-item measure of perceived social pressure or expectations of significant others that one will donate blood within the next 8 weeks.	“The people who are most important to me think I should give blood in the next 8 weeks.”	(1) Disagree to (7) Agree
Blood donation perceived behavioral control	A 6-item measure of one’s confidence and perceived ability to donate blood within the next 8 weeks.	“How confident are you that you will be able to donate blood within the next 8 weeks?”	(1) Not very confident to (7) Very confident
Blood donation intention	A 3-item measure of one’s intention to donate blood within the next 8 weeks.	“I plan to donate blood in the next 8 weeks.”	(1) Disagree to (7) Agree
Blood donation decisional balance	A 12-item measure of the pros and cons of blood donation, which contains three subscales – Pros, Physical Cons, and Eligibility Cons.	“I may be helping somebody in my community.”	(1) Not at all important to (5) Extremely important
Blood donation moral norm	A 3-item measure of perceived moral correctness associated with the act of donating blood.	“I feel a moral obligation to give blood.”	(1) Strongly agree to (7) Strongly Disagree
Blood donation anticipated regret	A 3-item measure of negative feelings associated with failing to act in accordance with one’s intention to donate within the next 8 weeks.	“If I do not donate blood within the next 8 weeks, I will regret it.”	(1) Very unlikely to (7) Very likely
Blood donation anxiety	A 3-item measure of anxiety expected during blood donation.	“If I donate blood I will feel nervous.”	(1) Not at all to (7) Very much