Answers.Body: <p>From what you describe it sounds like the deduping is happening within each group rather than <strong>before</strong> the recipients are split into A, B and final groups.</p>
  
  <p>You could confirm this by doing:</p>
  
  <p>Test 4: 8 contacts sharing same email with A/B - 25% to A and 25% to B and 50% to FINAL</p>
  
  <p>I would expect the same results as for test 3: 1 delivered to A mailing, 1 delivered to B mailing, and 1 delivered to Final mailing.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2016-04-02T02:32:20.657Z
Answers.LastActivityDate: 2016-04-02T02:32:20.657Z
Answers.UserDisplayName: JoAnne
Body: <p>Client is asking why 4 emails have been delivered to 4 contacts who all have same address.</p>
  
  <p>Test1: tested with 2 contacts and didn't use A/B testing. </p>
  
  <p>Outcome: was told would be delivered to ~1 address and was only 1 delivered - GOOD</p>
  
  <p>Test2: tested with same 2 contacts with A/B - 50% to A and 50% to B (so no FINAL mailing) </p>
  
  <p>Outcome: was told would be delivered to ~1 address and was only 1 delivered (to A mailing) - GOOD </p>
  
  <p>Test3: tested with 4 contacts sharing same email with A/B - 25% to A and 25% to B and 50% to FINAL</p>
  
  <p>Outcome: was told would be delivered to ~1 address. Had 1 delivered (to A mailing), 1 delivered to B mailing, and 1 delivered to Final mailing - BAD</p>
  
  <p>So I think A/B testing is causing 'dedupe by email' to break</p>
  
Comments.ContentLicense: CC BY-SA 3.0
Comments.CreationDate: 2016-04-02T00:54:12.457Z
Comments.Text: Ok some more digging through mailing results and evidence is very strong that 'dedupe by email' is only failing when A/B testing was deployed
Comments.UserDisplayName: petednz - fuzion
Tags: <civimail><duplicate-contacts><abtesting>
Title: Why does A/B testing cause 'dedupe by email' to fail when sending CiviMail to contacts with same email address
ThreadText: # Why does A/B testing cause 'dedupe by email' to fail when sending CiviMail to contacts with same email address
  
  (Asked by: username_0 on 2016-04-02)
  
  Client is asking why 4 emails have been delivered to 4 contacts who all have same address.
  
  Test1: tested with 2 contacts and didn't use A/B testing.
  
  Outcome: was told would be delivered to ~1 address and was only 1 delivered - GOOD
  
  Test2: tested with same 2 contacts with A/B - 50% to A and 50% to B (so no FINAL mailing)
  
  Outcome: was told would be delivered to ~1 address and was only 1 delivered (to A mailing) - GOOD
  
  Test3: tested with 4 contacts sharing same email with A/B - 25% to A and 25% to B and 50% to FINAL
  
  Outcome: was told would be delivered to ~1 address. Had 1 delivered (to A mailing), 1 delivered to B mailing, and 1 delivered to Final mailing - BAD
  
  So I think A/B testing is causing 'dedupe by email' to break
  
  **Tags:** civimail, duplicate-contacts, abtesting
  
  > **Comments:**
  > **username_0**: Ok some more digging through mailing results and evidence is very strong that 'dedupe by email' is only failing when A/B testing was deployed  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2016-04-02. Score: 1 | Accepted answer
  
  From what you describe it sounds like the deduping is happening within each group rather than **before** the recipients are split into A, B and final groups.
  
  You could confirm this by doing:
  
  Test 4: 8 contacts sharing same email with A/B - 25% to A and 25% to B and 50% to FINAL
  
  I would expect the same results as for test 3: 1 delivered to A mailing, 1 delivered to B mailing, and 1 delivered to Final mailing.
  
  
  ---
  
  