Assessing the Impact of myHealth Rewards Program-related Communications on New Hire Enrollment
Conditions: Health Promotion, Wellness Programs
Sponsor: Geisinger Clinic

 
1 
Assessing the Impact of myHealth Rewards Enrollment Emails (NCT04047342) 
 
Study Protocol with Statistical Analysis Plan 
 
December 7, 2020 
 

 
2 
 
Study Protocol 
 
Purpose 
 
The purpose of the study was to evaluate, prospectively, the potential impact of 
different email message conditions (standard promotional email and loss frame) on enrollment 
in a wellness program (myHealth Rewards) by Geisinger Health Plan (GHP) members who have 
recently been hired at Geisinger. The current study was developed to test whether the loss 
frame email was more effective than a standard reminder email, particularly for a population 
that was new to the organization.  It was hypothesized that the loss frame email would increase 
enrollment more compared to the standard email. 
 
Methods 
 
Sample 
 
There were 831 new employees who received emails from July 16, 2019 to October 8, 
2019. Enrollment data was gathered until December 20, 2019. Of these employees, 7 were 
excluded for registering before the emails were sent (e.g., after learning about the program 
during new hire orientation). The final sample consisted of 824 employees. 
 
Control and experimental conditions 
 
Standard Email. The standard email mentioned the average premium savings, the speed 
and ease of starting the enrollment process, and the deadline for registering and having health 
measures on file.  The standard email also provided two button links for registering and finding 
free health screenings where health measures could be collected and registered at one 
convenient time and location. This group served as the active control group. 
 
Loss frame email. The loss frame email had a subject line suggesting that employees 
were currently "throwing away" a precise dollar amount by not participating and that they 
could therefore avoid missing out on substantial gains (i.e., savings) by taking action. This email 
contained and built upon all of the same information included in the standard email. 
 
Outcome measures 
 
The outcome measure was enrollment in the myHealth Rewards program. This measure 
was binary, and data was collected until December 20, 2019. Although the number of people 
who clicked on the link was planned as another primary outcome measure, this data was not 
collected due to administrative error. 
 
 
 
 

 
3 
Statistical Analysis Plan 
 
Binary logistic generalized linear models (GLMs) were used to analyze enrollment and as 
a function of experimental condition, with the standard email group as a reference group.  
Odds ratios (ORs) were calculated, along with 95% confidence intervals (CIs); two-tailed p-
values < 0.05 were used to determine statistical significance.  To represent effect size, the 
standardized statistic, Cohen’s d, was estimated using the formula 𝐿𝑜𝑔𝑂𝑑𝑑𝑠𝑅𝑎𝑡𝑖𝑜 × √3 𝜋
⁄  
(Hasselblad & Hedges, 1995). Raw percentages with 95% CIs were also presented in graphs. All 
analyses were conducted in R.