How Duplicates Are Handled

Four different things get called a duplicate, and only one of them needs a decision from you. What each is, and what you can do about it.

Being on several lists is not a duplicate

Worth saying first, because it is the thing people expect to be a problem and is not. A number can be on as many lists as you like and is still one contact. Somebody on Wardens, First Aiders and All Staff is one person with one name and one set of details.

It also means a message sent to several lists at once reaches each person once. Send to three lists that overlap heavily and the recipient count is the number of distinct people, not the sum of the lists.

Which person a row belongs to

When an imported row arrives, it is matched to somebody you already hold using two things, in this order:

Your own reference, if the file carries one. This is your identifier for the person — a student or staff number — and it is the more reliable of the two, because it does not change when their phone does.
The mobile number, if there is no reference or it matches nobody.

If neither matches, the row is somebody new.

The same person twice in one file

Files often list somebody twice — usually because a correction was appended at the bottom. The later row wins, and the earlier one is reported as duplicated within the file so you can see it happened.

Row 12:  S1049823, 07911 123456, Ada Lovelace, Dr Patel
Row 340: S1049823, 07911 123456, Ada Lovelace, Dr Ng     <- this one is used

Somebody you already hold

This is the only case that needs a decision from you, and it is the ordinary one: the second time you import a roster, most of it is people you already have. You choose what the file is allowed to do to their details on the columns step.

Fill in what is missing — anything you already hold is kept, and the file only fills the gaps. The safe default.
Use the file's values — the file wins for the columns it carries.
Leave their details alone — nothing about the person changes.

All three still add the person to the list. "Leave their details alone" means leave their details alone — you uploaded a roster, so the roster is what you get. Whether somebody is on a list and what their name is are two separate questions.

Here is the same row against the same stored contact under each choice:

Stored:   name "Ada Lovelace", tutor "Dr Patel", campus (empty)
In file:  name "A. Lovelace",  tutor "Dr Ng",   campus "Highfield"

Fill in what is missing -> Ada Lovelace, Dr Patel, Highfield
Use the file's values   -> A. Lovelace,  Dr Ng,   Highfield
Leave their details     -> Ada Lovelace, Dr Patel, (empty)

Set the choice once for the whole import, then change your mind per group or per person on the review step. If a hundred rows should be updated but three should be left alone, you do not have to decide a hundred times.

Empty cells never delete anything

An empty cell means "no information", never "delete what you hold". A three-column extract of names and numbers will not wipe the tutor, campus and course you hold for everybody in it — even under "Use the file's values", which applies only to the columns the file actually carries.

Somebody whose number has changed

If your reference matches an existing contact but the number is different, that is not a new person — it is the same person on a new handset. The existing contact keeps their place: the number moves and they stay on every list they were on, keep the details you hold, and keep their opt-out status.

You hold:  S1049823, 07911 123456, Ada Lovelace, on 3 lists
In file:   S1049823, 07911 999888, Ada Lovelace

Result:    S1049823, 07911 999888, Ada Lovelace, still on 3 lists

This is why carrying your own reference in the file is worth the trouble. Without it there is no way to tell a change of number from a new person, and you end up with the old number lingering on your lists.

These are counted separately in the review, and you can page through them before committing — a change of number changes who receives a message, so it is worth a look.

When the new number already belongs to somebody

Occasionally a file says one person's new number is a number you already hold for somebody else. That is not something we will resolve for you: it means either two people have been given the same number in your source system, or a number really has been reassigned. Both need a human.

Those rows are refused, reported with both people named, and left alone. Nothing is merged and nothing is overwritten. Sort out which record is right and import again.

Merging two contacts also means merging two records of what each person consented to. Doing that unattended is how somebody who asked not to be contacted ends up being contacted, so it is left as a decision for you.

Somebody already on the list

Not a conflict at all, and nothing to decide. Importing a list you have already imported adds nobody twice — the people already on it are simply left as they are, and only the new ones are added.

Adding a number by hand

The same check happens when you type a number into a list. If you already hold it, you are told immediately — with their name, and which lists they are on.

The label box is disabled when the person already has a name, and this is why: naming somebody who already has one does nothing. Their contact keeps the name it has, so a message would go on using the old one. Open the contact to change it, and it changes on every list.

Other organisations

Duplicates are only ever looked for within your own workspace. If somebody is a contact of another organisation using the service, that is invisible to you and yours is invisible to them — including their consent, which is theirs and not transferable.

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