If you have more than 50,000 subscribers, what should your test distribution percentage be per condition?

The recommended test distribution percentage for scenarios with more than 50,000 subscribers is 5%. This is based on best practices in email marketing, where a smaller percentage of the subscriber base is used for testing purposes to ensure that the results are statistically significant while still maintaining a large enough sample size for analysis.

Using a 5% distribution allows you to test different variations of your email campaigns (such as subject lines, content, or send times) without compromising the overall reach of your campaign too significantly. This percentage strikes a balance between obtaining meaningful insights from your test conditions and maintaining a strong enough control group to validate the performance of your communications.

When distribution percentages exceed this value, the risk increases of skewing the overall performance metrics derived from the entire subscriber list, as a larger portion of the list is being diverted into tests rather than receiving the standard campaign. By adhering to a 5% distribution for tests, marketers can ensure that they gather useful data without overwhelming their primary marketing strategy.