The ThinkPlayful™ app is a mobile app available on both Android and iOS devices that aims to engage, encourage, and empower parents in supporting their children's early learning and development. The app uses an innovative guided play approach, with activities that parents and children can do together both on- and off-screen. It is not managed or sponsored by the school.

The purpose of this study is to find out how the app engages parents and children in guided play to support early learning and development. We are inviting you and your child to take part in this study because we want to learn how the program may improve children's mathematical thinking and enhance parent-child interactions.

Participating parents will be asked to do the following:

• Fill out and return the consent form if you agree to participate in the study with your child

• Participate in an orientation on the use of the ThinkPlayful™ mobile app

• Be randomly assigned to either use the ThinkPlayful™ app from September to December of 2024, or after December 2024. Use the app at home with your child for 6 weeks, engaging in the recommended activities for at least 1 hour per week

• Use the app to communicate with your child's teacher, if you choose

• Complete a survey on parent-child interaction and your thoughts about parents, which will take 15-20 minutes

• If selected, participate in a 1-hour phone or Zoom interview with a WestEd researcher

If your child participates in this study, they will be asked to do the following:

• In September and December of 2024, trained assessors from WestEd will conduct pre- and post- assessments on your child's mathematical thinking. The assessments will take place during regular class time, with the teacher's permission and your child's assent. Each assessment will take around 20 minutes. Researchers would also like to collect some demographic information about your child, such as their gender and racial/ethnic background. All personal information about your child will be used for research purposes only, and will be kept confidential.

During the six-week study period, teachers will facilitate communication between you and the school at your convenience while your child engages with the app. Otherwise, classroom activities will proceed as usual.

Participation in this study is entirely voluntary. Declining to participate will not result in any penalties. If you choose not to participate, you will not have access to the app, and your child will not be asked to do any assessments related to this project. Additionally, none of your child's information will be shared with the research team. If you do decide to participate, you can withdraw from the study at any time with no consequences. If you choose to withdraw, please contact your child's teacher or the WestEd researcher.

No, there is no cost to participate. The app is provided free or charge to all participating parents for the duration of the study.

All data collected during the study will be used solely for research purposes to help improve the ThinkPlayful™ app's educational strategies and functionality. Your child's personal information will be kept confidential and will not be shared.

Participating parents and children may experience improved parent-child interactions, better preparedness for kindergarten, and enhanced mathematical skills. Additionally, your feedback will help improve the app for other parents and children.

There are minimal risks involved, primarily related to privacy and data protection. We will keep your information confidential.