How length and presentation of email copy impact clickthrough rate Experiment ID: #8902

Leadership Institute

Experiment Summary

Timeframe: 4/10/2018 - 4/23/2018

Leadership Institute was sending their monthly appeal to their email file, based on the direct mail letter that also went out during that month. They were curious to see how including the full text (including extra spacing) would perform as compared to a truncated email version of the copy that distilled the value proposition into a shorter length email.

They created both versions and split the housefile to test.

Research Question

How will length and presentation of email copy impact clickthrough rate?


C: Version A
T1: Version B


Treatment Name Click Rate Relative Difference Confidence
C: Version A 0.68%
T1: Version B 1.6% 136.4% 100.0%

This experiment has a required sample size of 1,003 in order to be valid. Since the experiment had a total sample size of 23,365, 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:

    136.4% increase in traffic
× 0% increase in conversion rate
× 0% increase in average gift

Key Learnings

The truncated version produced a 136.4% lift in clickthrough rate, as the links were much more accessible in the copy. However , a further review of the data showed that the two treatments produced the exact same number of conversions—meaning that there was a decrease in conversion rate for the shorter message. This suggests a new test that presents a longer message with the reduced spacing of the shorter message.

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Experiment Documented by...

Jeff Giddens

Jeff is the President at NextAfter. If you have any questions about this experiment or would like additional details not discussed above, please feel free to contact them directly.