There is a difference between an address search and a fiduciary confirmed locate.
The address search can be (1. The current best address or 2. A address history). Then giving the information back to the requestor, the requestor sends the participant a letter. Hoping for the best.
However, not all addresses provided are good. What most clients are looking for is the "Best Mailing Address." Most of the time, it is the case. However, sometimes it is an activity history based on the participant's information. Example: If a participant has rentals, pays for their college kid's utilities, or the participant has moved but never updated the utilities with their new address. The address(es) are associated with the participant but are not necessarily the "Best Mailing Address." For that, you need to reach out and touch; That takes a Fiduciary Confirmed Locate. And with Covid causing internal resettlement of participants, that can be challenging.
The Fiduciary Confirmed Locate is a deeper, more formal look and search into a participant. I always recommend cleaning and confirming the PII data of the participant to be searched first. Then search for the participant after the cleansing and verification. Why? You might be looking for a deceased participant, and you need to look for a beneficiary. Or the SSN & name may have been borrowed or highjacked. Or there is a transposition error in the SSN or DOB. You may have middle names mixed in with your first names or suffixes mingled with your last names. Or in cases of unfamiliar cultures, the first and last names are switched or are incorrect. Or, as with a good friend of mine, they never updated their address with the utilities and had the two best mailing addresses.
