Huge difference in opening rate between sender addresses

[SLee28]

Hi Hubspot community,

We are encountering a strange issue, and any insights will be appreciated.

We usually alternate the sender of our marketing emails between our two directors. However, we've recently noticed a consistent 4-5% difference in open rates depending on which director is the sender. This has only been a consistent trend since mid-last year.

We've checked sender reputation, and neither director is flagged as spam. Surprisingly, the director whose emails have a lower open rate actually has a better sender score.

Does anyone have insights into why this might be happening? We're investigating and any input would be greatly appreciated.

[karstenkoehler · Accepted solution]

@SLee28 I don't see any reasons why any technical configuration should affect the performance. The difference is only cosmetic. I really think that this is due to different names / addresses performing differently due to how they are perceived.

[franksteiner79 · Accepted solution]

Just chiming in here @SLee28.

My two cents, which I keep harping on abot, stop taking open rates seriously - they are notoriously unreliable, and depending on the recipients ESP and email client, can either be artifically inflated or deflated. 

A more important question would be which of the two emails has the most clicks?

Which one drives the most website visits and conversions, or whatever your ultimate goal with these emails is. How do these, more tangiable KPIs compare for each sender variation?

Frank

[ManharChaurasia]

Hi @SLee28,

Even with good sender scores, open rates can vary based on factors like how familiar recipients are with the sender’s name, past engagement, or even subtle differences in tone or timing.

Sometimes one sender just “feels” more personal or recognizable to the audience, which can impact opens. It’s not always about reputation—sometimes it’s just how the name lands in the inbox.

[karstenkoehler]

Hi @SLee28,

The most obvious hypothesis would be that one of the email from names / from addresses seems more trustworthy / relevant / interesting. It doesn't necessarily have to be due to reputation, especially if you checked and ruled out other indicators.

It's hard to verify this hypothesis unfortunately.

Best regards

[SLee28]

We are unsure about this, as we operate in a niche space and we dont have a huge marketing contact list. We would assume that most people on the lists would recognised our directors' name.

[karstenkoehler]

@SLee28 people don't have to know a person to make a judgment: https://www.business-standard.com/article/news-ians/easy-names-inspire-trust-in-strangers-study-1140...

If you're saying you don't have a huge marketing contact list, which sample size are we talking about? If the lists are small, it might look like a pattern but not be statistically significant. https://www.surveymonkey.com/mp/ab-testing-significance-calculator/

[SLee28]

We have around 5500 makreting contacts. It is hard for us to believe the name could be the reason as this has only been an issue since last year. Do you think there would be other possible reason, or technical reason?

[karstenkoehler]

@SLee28 have you ran the numbers through the statistical significance calculator? Can you share the number of opens for sender A vs B and the exact count of sent emails?

[SLee28]

Hi we just ran the numbers, Director A got 21.65% and B got 17.72%. 

[karstenkoehler]

@SLee28 I can't run the analysis with that, unfortunately, can you please give me the number of emails sent and number of opens per director?

[SLee28]

A - Total sent: 598652 Total Opened: 129580

B - Total sent: 381852 Total Opened: 67670

[karstenkoehler]

@SLee28 is there a typo in the first opened? You mentioned an open rate of 21.65%, this is 32.50%.

[SLee28]

Sorry there is a typo but it is on B, the correct numbers should be:

A - Total sent: 598652 Total Opened: 129580

B - Total sent: 381242 Total Opened:67670

[karstenkoehler]

@SLee28 this is indeed a statistically significant result – still, I don't necessarily think that this due to any technical reasons. I assume you're sending from the same connected email sending domain, only changing the from addresses?

[SLee28]

Yes we do, only the "from address" is different.

[karstenkoehler · Accepted solution]

@SLee28 I don't see any reasons why any technical configuration should affect the performance. The difference is only cosmetic. I really think that this is due to different names / addresses performing differently due to how they are perceived.

[SLee28]

Thank you so much for your help.