29 Nov 2022

Last year, we sought to answer the question below by examining the so-called “holiday effect” on engagement rates of BulletinHealthcare email briefings (eNewsletters).

“Do mailings sent in late December have engagement rates that differ from average?”

Counter to the common notion that email engagement drops during the holiday season, we found that engagement rates for mailings sent before Christmas actually improved during the business days directly after the holidays. Our data determined that there was a longer lag time between the day an email was sent and the day it was opened, which lead to the conclusion that most HCPs will typically catch up with any missed briefings after Christmas. This is great news for our advertisers as their ads will always appear in a given briefing, regardless of the date or time opened.

This year, we decided to repeat our experiment by examining open rates and click-through rates (CTR) in 2021 to see if our conclusions held true.


We began this year’s experiment by taking a closer look at open rates for three engagement periods in 2021:

  • December Average: 12/1 – 12/20
  • Pre-Christmas: 12/21 – 12/23
  • Post-Christmas: 12/27 – 12/30

The chart on the left displays the day of send average open rates, email opens that occurred on the same day the email was sent. The chart next to it displays the open rates for the same newsletters but takes into account the so-called “long-tail opens”, in other words, email opens that happened a few days after an email was sent.

As you can see, while there was a small, not statistically significant difference of 1% in open rates for emails sent in the last few business days directly before Christmas (39.8%) and the average December open rates (40.8%), this difference became virtually non-existent by mid-January (44.4% vs 44.5%, respectively). This suggests that while the emails sent before holidays might sit in recipients’ mailboxes for a few days, they will eventually be read once the holidays are over.

Another important takeaway from these charts is that emails sent directly after the holiday (at the end of December) had higher open rates than those sent on any December day, both on the days they were sent and a few days after. This demonstrates an unexpected value in advertising during the aforementioned ‘Post-Christmas’ engagement period!

What about the click-through rates?


The click-through rate data tells us a similar story: a small, non-significant gap in CTR on the days preceding Christmas which seems to be closing a few days later, once email recipients return to their regular routine.

We took these findings a step further and explored the dynamics of engagement by examining the number of days between an email’s day of send and a recipient’s day of open.

The chart above tells us the following story: Imagine you send a newsletter today to 100 recipients. If today is a typical day, then by tomorrow 78 of your recipients will have opened your mailing. However, if today is the last business day before holidays or the first business day right after the holiday, then by tomorrow only 75 people will have opened your email instead.

Note that the gap in cumulative percentage of opens between mailings sent on a typical day (blue line) and those sent on the first business day after holidays (green line) closes at day 7. At the same time, it takes about 14 days for mailings sent right before the holidays (light-blue line) to catch up with the two other mailings. This means that two weeks later, around 97 of your 100 imaginary recipients will have read the email, regardless of when you sent it.

To conclude with the original question, do mailings sent in late December have engagement rates that differ from average? The answer lies in the data. Our data shows us that HCPs will still engage with mailings and your advertisements as normal, regardless of whether the mailing is sent before or after the holidays. The only difference is that it may take a little longer to see this reflected in your campaign metrics.

To learn more about how BulletinHealthcare can help YOUR brand achieve its goals during the holiday season and beyond, reach out to us at advertise@bulletinhealthcare.com.

*All metrics are adjusted for the effect of IOS 15.