We're seeing event sign-ups for multiple (non-member) participants that are made by one (non-member) person - in our case, a parent registering two children to two different swim trainings. They correctly get individual registration-confirmation emails, stating their individual names, but in our system it looks like only one participant booked two different events. The other person is completely missing in CiviCRM. Is this a bug?

For context, this is the (currently newest) version 5.68.0 on (currently newest) WP 6.4.2, and the event registrations contain a mandatory field for email address. Obviously in this scenario, the parent will use the same email address for both registrations.

This answer to a closely related question indicates that the "default unsupervised rule says individuals with matching email addresses are the same person". Our events are indeed set up using that rule "Email address (reserved) unsupervised" but the wording of this is confusing me.

Should we simply blank out the rule field, and not use any deduplication rule? should we use name+email? Supervised or unsupervised; what does that even mean? I really don't understand the event documentation about this, nor the deduplication documentation.

We don't actually care whether we end up with duplicates in our system. Each event is separate, and each participation is separate. We do not need to know whether some participant might have participated before.

Side note: if it turns out that we need to change the dupe setting, how can we do that for 20+ events at once, rather than having to manually edit each one separately?

  • Supervised means that an admin is entering data, hence on the screen they will have suggestions about possible matches. Unsupervised is for non-admins filling in forms. But the key is to use a Rule which avoids it saying 'ah they are using this email therefore they are the same person' since that can result in overwriting of First/Last etc
    – petednz - fuzion
    Commented Jan 4 at 21:41
  • Manual says: The 'Supervised' rule for each contact type is automatically used to check for possible duplicates when contacts are added or edited via the user interface. The UI will alert the user if a contact they are creating matches another contact using the rule. The user can then decide whether to edit the existing contact or to continue to create a new contact. Supervised Rules should be configured with a broader definition of what constitutes a duplicate as the user can decide whether to act on the rule or not."
    – petednz - fuzion
    Commented Jan 4 at 21:43
  • If you think that can be clarified better then you are welcome to propose an edit
    – petednz - fuzion
    Commented Jan 4 at 21:43
  • "Supervised means that an admin is entering data" > but this is a public sign-up form for non-members, so the rule "name+email (reserved) supervised" doesn't make any sense; yet that's present out of the box. Commented Jan 4 at 21:48
  • I'd love to improve the documentation but first I need to understand how the system really works :-) Commented Jan 4 at 21:48

1 Answer 1


Status: It looks like the default behaviour of CiviCRM prevents the use of the same email address for multiple participants.

  1. If an event specifies no rule, then the default applies: that is "Email (unsupervised)" and yes, that prevents the use of the same email address for multiple participants.
  2. There's a rule "Name and Email (supervised)" which sounds good (because the name would be different while allowing the email address to be reused), but "supervised" means that it's only available for admins and this can't be used for public sign-up pages used by non-members.
  3. There's a rule "Name and address (general)" which apparently doesn't care about the value of the email address. Maybe that's useful, I don't know.
  4. It's unclear to me why the registration-confirmation emails are sent out with correct individual names. Apparently the problematic deduplication only happens after sending the email. (Side note: the payment processing also shows the deduplicated name, not the expected individual names. This appears to be a bug and needs to be reported via established channels (I don't know what those channels are).


  1. First, determine whether "Name and address (general)" might be used and if so then continue with step 5 below; otherwise create a new rule as follows:
  2. In CiviCRM, navigate to Contacts > Find and merge duplicate contacts.
  3. Under Person rules, click Add New Person Rule.
  4. Enter a rule name, then select first name + last name + birth date (not email address). Then give each field a weight of 1. Then enter the sum (3) as threshold value. Save.
  5. In CiviCRM, navigate to Events > Manage events.
  6. Edit every event by clicking Configure > online registration, then choose your new duplicate matching rule, then Save.

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