Alliance Defending Freedom

How a more casual subject line impacts opens

Experiment ID: #18644

Alliance Defending Freedom

Alliance Defending Freedom is an alliance-building legal organization that advocates for the right of people to freely live out their faith.

Experiment Summary

Timeframe: 07/12/2019 - 07/16/2019

Alliance Defending Freedom was continuing the longitudinal experiment to increase cultivation to a targeted segment of their email house file. The goal of these emails was to simply engage the audience and provide them with ongoing content and stewardship. With that in mind, we wanted to find ways to increase that engagement.

Since these emails were intended to appear as if they were one-to-one communications, we wanted to see if a more casual subject line could impact the open rate. This would be compared the to more straight-forward subject lines often used.

Research Question

Will a more casual subject line increase email open rate?

Design

C: Control
T1: Treatment #1

Results

 Treatment NameOpen RateRelative DifferenceConfidence
C: Control 19.9%
T1: Treatment #1 21.5%8.1% 100.0%

This experiment has a required sample size of 4,904 in order to be valid. Since the experiment had a total sample size of 61,123, and the level of confidence is above 95% the experiment results are valid.

Flux Metrics Affected

The Flux Metrics analyze the three primary metrics that affect revenue (traffic, conversion rate, and average gift). This experiment produced the following results:

    8.1% increase in traffic
× 0% increase in conversion rate
× 0% increase in average gift

Key Learnings

With the more casual “I can’t even imagine…” subject line, we saw an 8.1% increase to email opens. This subject line had two key differences from the control: 

  1. It created a mystery that the reader would only solve by opening the email
  2. It was far more personal using the “I” in the subject

To know which of these factors had the biggest impact, we would need to isolate them individually in a future experiment.


Experiment Documented by NextAfter

Question about experiment #18644

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