In this application, a randomized controlled trial will be used to test the hypothesis that small financial incentives can be used to increase post-operative ambulation. The randomized controlled trial design is necessary to demonstrate a causal relationship between the intervention (provision of financial incentives)and the outcome (increased ambulation). This design will also provide preliminary data (e.g. effect sizes, feasibility) needed to design larger trials that will determine whether increases in ambulation produced by financial incentives can be translated into decreases in clinically relevant outcomes such as post-operative complications, readmissions, and functional decline in patients undergoing major abdominal surgery.

All participants will receive education about the importance of early ambulation and knowledge of their daily step goals. A Fitbit Zip, a commercially available activity tracking device with the ability to record and wirelessly upload step counts, will be provided to each participant to measure the outcome of daily step counts for a lead in period of 1-2 weeks before surgery and 30 days after surgery with the option for patients to continue to submit data independently for up to 90 days after surgery. The lead-in period will provide data to determine a patient-specific daily step count baseline. Step count goals will change each week and be determined by a set-percentage of the patient-specific baseline. The percentages will be as follows: 10% of baseline for week 1, 25% of baseline for week 2, 40% of baseline for week 3, and 55% of baseline for week 4. Data will be collected using the Way To Health platform, a digital platform specifically designed to facilitate randomized controlled trials testing interventions increase health promoting behavior.

Participants will be randomized using simple balanced randomization into one of two arms: "control" or "financial incentives". Individuals will be informed if they fail to achieve adequate steps and would have otherwise been eligible for payments in order to leverage regret aversion. The financial incentive is framed as a "gain" rather than a "loss" because striving to achieve a positive reward may provide the necessary support to positively motivate patients who just had major, painful surgery. Small definite payments are combined with larger lottery-based payments to provide ongoing feedback coupled with the possibility of winning a higher magnitude reward. Automated notification about payments will be delivered through the participant's preferred mode of communication (e.g., phone call, email). Patients will track their earnings and step count over time through Way to Health.

Beginning shortly before the planned surgery and continuing for 30 days after date of surgery, all participants will use Fitbit Zips to measure daily step counts. Patients will have the option of submitting up to 90 days of post-operative data. Post-operative ambulation has been repeatedly demonstrated to be beneficial to recovery by a number of different metrics, and the Zip device has been shown to be an accurate measure of step counts. The Stanford Health Assessment Questionnaire (SHAQ) is a broadly used and validated questionnaire which, in its shortened form, assesses subjects ability to perform 20 different actions and the need for assistance with these actions. It also captures patients global assessments of pain and well-being. This will be administered preoperatively, 30 days post-operatively, and 90 days postoperatively to measured post-operative functional decline. The International Physical Activity Questionnaire (IPAQ) Short Seven Day form quantifies patient reported levels of physical activity over the seven days prior to the interview. It is similarly broadly used and has been previously validated against accelerometer data. This will be administered preoperatively, 30 days post-operatively, and 90 days postoperatively to measure post-operative decline in physical activity and to discover differences in baseline physical activity that are not captured by preoperative step-count data.The Multidimensional Scale of Perceived Social Support (MPPSS) is a validated tool for assessing patient's self-assessed degree of support from others. Prior research has suggested social support as an important factor in exercise behavior, which is consistent with our clinical observations. This will be administered pre-operatively and a 30 and 90 days post-operatively to help account for confounding by this important and otherwise unmeasured variable.