The purpose of the study is to evaluate, prospectively, the potential impact, on myHealth Rewards wellness program enrollment prior to the 2019 November submission deadline, of sending different messages via email to Geisinger Health Plan (GHP) members who have just been hired.

The myHealth Rewards wellness program managed by GHP rewards those GHP members who carry their insurance through employment at Geisinger with reduced health insurance premiums over the course of the following year, if members register for the program and have their health measures on file by the enrollment deadline and are then able to meet their health goals by the respective due date. In spite of the potential savings to health plan members and the wellness program's potential to motivate engagement in healthy activities (with consequent improvement in health outcomes), about 23% of eligible existing GHP members did not enroll during the primary 2019 enrollment period, even after receiving promotional email communications and reminders. Therefore, the current study was developed to test whether a revised version of a standard welcome email is more effective than the standard email in increasing myHealth Rewards login and enrollment rates. The standard welcome email is what would typically be sent by GHP to encourage enrollment among new hires; it mentions the benefits of enrollment (maintaining good health and saving money on insurance premiums), the average premium savings, the ease of the registration process, and the deadline for registering and having health measures on file, plus it provides registration steps and hyperlinks for registering and finding free health screenings where health measures can be collected and registered at one convenient time and location. The loss frame email recommends that GHP members not "throw away" a precise monetary amount in savings by not participating and that they can therefore avoid missing out on substantial gains (i.e., savings) by taking action. It is hypothesized that, on average, the loss frame email will increase enrollment compared with the standard email, among this population of new hires for whom this is only the second time that they have been informed about myHealth Rewards. Findings will help inform how best to increase enrollment in a wellness program among health plan members who are new to the system.

Inclusion Criteria:

• Any Geisinger new hire, regardless of benefits status, who started on or after July 1, 2019 and before November 30, 2019

Exclusion Criteria:

• Existing Geisinger employees hired prior to July 1, 2019
• New hires who do not have an email address on file

The population consists of new Geisinger Health Plan members who are benefits subscribers.

Data with no personally identifiable information will be made available to other researchers on the Open Science Framework for transparency. This will include the essential data and code needed to replicate the analysis that yielded reported findings. The PI did not examine or analyze any data from this study prior to this registration.

The data will become available after publication of study results in a scientific journal and will be available as long as the Open Science Framework hosts the data.

The data on the Open Science Framework will be open to anyone requesting that information.

The baseline outcome measure was not applicable, since enrollment and login in response to the email was the outcome. There was no previous email, and participants were selected for not having enrolled in the year of the study period.

No adverse events were evaluated.

We only received aggregate information about email engagement with no individual-level information collected (including those for adverse events).

For this study, we only received data about engagement with the email (specifically, only enrollment). Individual patients were not identified and demographic information such as age, sex, or gender were not collected.