Increasing Low-income Children's Access to Healthy Structured Programming to Reduce Obesity - Disparities in overweight and obesity (OWOB) prevalence between children (ages 5-11) from low- and middle-to- high-income families persist. The structured days hypothesis posits that structure within a day, defined as a pre- planned, segmented, and adult-supervised compulsory environment (like a school day), plays a protective role for children against obesogenic behaviors and, ultimately, prevents the occurrence of negative health outcomes, such as excessive weight gain. Essentially, the structured days hypothesis draws upon concepts in the ‘filled-time perspective’ literature which posits that time filled with favorable activities cannot be filled with unfavorable activities. There are at least two “windows of vulnerability” for children outside of the school day. These critically important windows include the hours immediately following school (i.e., 3-6pm school days) and the 10 weeks of summer vacation. Programs that can provide a healthy structured environment and prevent unhealthy weight gains exist for both of these time periods (i.e., afterschool programs and summer day camps). Unfortunately, these programs are too expensive for children from low-income families to attend. Thus, based on demand-side financing, which has a long history addressing large scale public health problems in the United States through federal, state, and local programs like the Supplemental Nutrition Assistance Program and the 21st Century Learning Centers Program, we will rigorously test the impact of providing access to pre-existing, community- operated afterschool and summer programs on weight status (i.e., BMI z-score) and obesogenic behaviors (i.e., physical activity, screen use, diet, and sleep) of elementary children from low-income households. This approach will potentially be less costly than current obesity treatment programs which cost up to $4,600 per child. This study will employ a 2x2 full factorial design. The four groups will be a no-treatment control, afterschool program voucher only, summer day camp voucher only, and vouchers for afterschool and summer day camp combined. We will accomplish the following specific aims: AIM 1: Compare differences in primary and secondary outcomes among children provided no voucher, a voucher for after-school only, a voucher for summer camp only, and a voucher for both after-school and summer camp. AIM 2: Evaluate the cost-effectiveness of providing a voucher for after-school only, a voucher for summer camp only, and a voucher for both after-school and summer camp. Aim 3: Evaluate facilitators and barriers to the implementation, effectiveness, and sustainability of the voucher program by conducting qualitative interviews with key stakeholders (i.e., children, parents, staff, administrators). This study is significant because nearly one in five children are obese, and disparities in OWOB exist between children from low- and middle-to-high-income households persist despite past school-based interventions. This study is innovative because it represents one of the first attempts to provide access to healthy structured programming during two “windows of vulnerability” for children outside of the school day. Should the proposed intervention strategy prove effective, it has the potential to mitigate disparities in OWOB prevalence.