To ensure unbiased results, consider the following practices: 1. Random Sampling: Use random sampling techniques to select email recipients, ensuring a representative sample. 2. A/B Testing: Conduct A/B tests to compare different versions of emails objectively. Ensure that the test groups are similar in size and characteristics. 3. Clear Metrics: Define clear, objective metrics for success, such as open rates, click-through rates, and conversion rates. 4. Transparent Reporting: Report all results, both positive and negative, to get a comprehensive view of the campaign's performance.