Effects of a Digital Micro-Movement Nudge Intervention on Well-Being and Academic Outcomes in College Students

State anxiety will be assessed using the 6-item Spielberger State-Trait Anxiety Inventory STAI-6 (Marteau & Bekker, 1992). Six items (e.g., "I was worried these past 2 weeks.") rated from 1 (Not at all) to 4 (Very much so) will be averaged for a composite score. Higher scores indicate greater levels of anxiety.

Procrastination will be assessed using six items from the Irrational Procrastination Scale (Steel, 2002), such as "At the end of these past 2 weeks, I know I could have spent the time this week better." Participants will respond on a 1-5 scale (1 = Very seldom or not true of me, 5 = Very often true, or true with me), and higher average scores indicate higher levels of procrastination.

Productivity will be assessed using the Task Performance subscale of the Individual Work Performance Questionnaire (IWPQ; Koopmans et al., 2013, 2014), adapted to the academic context. Participants will respond to five items (e.g., "I was able to plan my work so that I finished it on time") with reference to their schoolwork. Items will be rated on a 6-point scale from 0 (seldom) to 5 (always) and then the scores will be averaged, with higher scores indicating greater productivity.

Study burnout will be measured using the 9-item Study Burnout Inventory (Salmela-Aro & Read, 2017). Participants will indicate how well each item described their experiences (e.g., "I felt a lack of motivation in studying and often think of giving up") on a 6-point scale from 1 (Completely disagree) to 6 (Completely agree). Scores will be averaged, with higher scores indicating greater academic burnout.

Study engagement will be measured using the 9-item Study Engagement Inventory (Salmela-Aro & Read, 2017). Participants will rate items such as "I found studying full of meaning and purpose" based on their experiences. Responses will be given on a 6-point Likert scale ranging from 1 (Completely disagree) to 6 (Completely agree) and higher scores will indicate greater levels of academic engagement.

Implementation intention will be measured using the single item "In the past 14 days, I have taken steps to achieve my goals for the month." scored from 1 (Strongly disagree) to 5 (Strongly agree), where a higher score indicates higher implementation intention.

Goal progress will be measured using the single item "In the past 14 days, I have seen progress towards my goals for the month." scored from 1 (Strongly disagree) to 5 (Strongly agree), where a higher score indicates higher goal progress.

Depression will be measured using an adapted version of the 10-item Short Depression Scale Revised (CES-D-R 10) (Andresen et al., 1994). The scale includes the sample item "I felt that everything I did was an effort." and is scored from 1 (Rarely or none of the time) to 4 (All of the time). Scores will be averaged and higher scores indicate higher risk of depression.

Life satisfaction will be measured using an adapted version of Diener's Satisfaction With Life Scale (SWLS). The scale includes 5 items e.g. "In most ways, these past 2 weeks have been close to ideal" and is scored from 1 (Strongly disagree) to 7 (Strongly agree) (Diener et al., 1985). Scores will be summed and higher scores indicate higher life satisfaction.

Perceived stress will be measured by an adapted version of the 4-item Perceived Stress Scale (PSS) developed by Cohen and colleagues (Cohen et al., 1983). One sample item includes "In the last 2 weeks, how often have you felt difficulties piling up so high that you could not overcome them?" and items are scored from 0 (Never) to 4 (Very often). The composite score is calculated by summing the scores of all items; higher scores indicate higher levels of perceived stress.

Positive Affect (PA) and Negative Affect (NA) will be evaluated using the Circumplex Model of Affect (Russell, 1980). Participants will rate feelings such as 'Energetic' and 'Dejected' experienced over the past two weeks, from a scale of 1 to 5 (1 = Not at all, 5 = Extremely).

Coping strategies will be assessed using the Brief COPE (Carver, 1997) which is a 28-item self-report measure assessing a range of adaptive and maladaptive coping responses to stress. Participants will indicate how frequently they have engaged in various coping behaviours in response to stress over the past two weeks (e.g., "I've been taking action to try to make the situation better"). Items will be rated on a 4-point scale from 1 (I haven't been doing this at all) to 4 (I've been doing this a lot). Scores will then be averaged for each coping strategy, with higher scores indicating greater use of that coping strategy.

Emotion regulation will be assessed using the Emotion Regulation Questionnaire (ERQ; Gross & John, 2003), which is a 10-item self-report measure assessing two emotion regulation strategies: cognitive reappraisal and expressive suppression. Participants will indicate the extent to which they agree with statements describing how they typically regulate their emotions (e.g., "I control my emotions by changing the way I think about the situation I'm in"). Items are rated on a 7-point scale from 1 (strongly disagree) to 7 (strongly agree). Subscale scores will be computed by averaging items corresponding to cognitive reappraisal and expressive suppression, with higher scores indicating greater use of the respective emotion regulation strategy.

Self-control capacity will be assessed using the Brief State Self-Control Capacity Scale (BSSCS; Lindner et al., 2019), which is a 5-item self-report measure assessing individuals' perceived momentary self-control resources. Participants will indicate the extent to which each statement reflects their experiences over the past two weeks (e.g., "I felt like my willpower was gone"). Items are rated on a 7-point scale from 1 (not true) to 7 (very true). Items will be averaged to compute a composite score, with higher scores indicating greater state self-control capacity.

Perceived health will be assessed using a single-item self-report measure of general health status. Participants will respond to the question, "How would you rate your physical health over the past two weeks?" Responses will be rated on a 5-point scale from 1 (Poor) to 5 (Excellent). Higher scores indicate better perceived physical health.