My Dedupe rule is not working at all. I have it set to first name, last name, phone all with a weight of 10 and a weight threshold of 30. It appears like it is not working at all. I have many people that match on all 3 fields that are creating duplicates. This is happening on both contribution pages and event forms. Do I have the rule set up incorrectly or am I missing anything?
Perhaps the best free explanation of CiviCRM's deduplication is from the CiviCRM blog last year (July 31, 2014): Understanding CiviCRM Dedupe Rules
For the whole process, I will let the author speak for themselves as it really is an excellent write up and worth reading in its entirety to understand the deduplication system.
For this question, I suspect the issue comes down to the usage of the rule.
Quoting the author of the blog post (from point 2):
Unsupervised rules are rules that are automatically checked when a user enters contact info into a form on the front end of the site (for example, when registering for an event, making a contribution, etc.). If a match is found, CiviCRM automatically merges the new contact into the old one, without checking with the user....
Supervised rules, on the other hand, are rules that are automatically checked when an admin or staff member enters info into the back end of the site (i.e., the admin interface). They do not automatically merge the contacts — they just trigger a pop-up suggesting that the contact may be a duplicate....
General rules are not triggered automatically at all. They can be run manually from the "Find and Merge Duplicate Contacts" page, or selected to run during a data import, but they do not ever just run on their own....
Rachel, based on your question, it looks as though your rule is setup correctly, but it is most likely set as a general rule, not the unsupervised rule for individuals. If you change the usage, I think you will find the results you're looking for.
You don't say what version of CiviCRM you are on, and you do say this is occurring on both contributions and on event registrations, but I will note here (for those happening onto this related issue) that there is a bug in CiviEvent, versions 4.3.4, 4.4.3, in which the unsupervised matching rule is not used in event registrations. See: https://issues.civicrm.org/jira/browse/CRM-14134
The fix for this is in version 4.5. We are currently examining the fix to see if it can be applied to earlier versions.