> For the complete documentation index, see [llms.txt](https://docs.dinmo.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.dinmo.io/identity-resolution/survivorship-rules.md).

# Survivorship rules

Survivorship rules define how DinMo chooses the winning value for each field in the [golden record](/identity-resolution/golden-record.md).

They are used when several source records are merged into the same [`dinmo_id`](/identity-resolution/dinmo-id.md) and more than one value is available for a golden field.

## Available strategies

| Strategy             | What it does                                               | Use it when                                           |
| -------------------- | ---------------------------------------------------------- | ----------------------------------------------------- |
| Last non null        | Keeps the most recent non-empty value.                     | The latest known state should win.                    |
| Most frequent        | Keeps the value observed most often across merged records. | The most consistently observed value is more trusted. |
| Model Priority Order | Keeps the value from the most trusted model.               | One source is more authoritative than the others.     |

## Examples

| Field           | Suggested strategy                                                |
| --------------- | ----------------------------------------------------------------- |
| Email           | Most frequent or Model Priority Order, depending on source trust. |
| Phone number    | Most frequent or Last non null.                                   |
| Consent status  | Model Priority Order if one source is authoritative.              |
| Last login date | Last non null.                                                    |

## How to choose

Choose the rule that matches the business meaning of the field:

* use **Last non null** for freshness
* use **Most frequent** for consistency
* use **Model Priority Order** for trusted systems of record

Review high-impact fields before activation. See [Review and monitor](/identity-resolution/profile-resolution/review-and-monitor.md) for the validation workflow.


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