# Preview & Metametrics

As fields are introduced or updated, Lumi AI will process the source system to retrieve example records and aggregate information about the target fields.

## Preview (Sample Records)

Sample records (referred to as the "Preview) are made available as the definition is updated. These are 5 selected rows choosen at random from the system. You can use this information to examine arbitrary data to make sure you've picked the right data, custom fields are working as intended, or to check for nulls (see further on "Metametrics" below).

<figure><img src="/files/tFESg1XctsfJsnGFvSAN" alt=""><figcaption></figcaption></figure>

If the definition is unchanged and the preview otherwise appears stale, you can use the "Refresh" button to do an updated pull.

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{% hint style="info" %}
Note that, depending on the source system, the records may not be fully random. Using "Refresh" in such cases may always pull the implied-order first 5 records.
{% endhint %}

## Metametrics (Summary Data)

"Metametrics" refers to Lumi AI's subset of aggregate information that is pulled from the system. This can be useful to determine attributes like the date range of the data, if fields are sparsely-populated, or if the data in the field is non-unique (duplicates are present).

You can view Metametrics by clicking the Advanced toggle within Preview.

<figure><img src="/files/STxiocM5c8CiEeOjpdt8" alt=""><figcaption></figcaption></figure>

The metrics include:

* Count — Basic count of the records
* Unique Count — Count of truly unique records
* Null Percentage — The proportion of null records in the field
* Minimum Value — The lowest alphanumeric record
* Maximum Value — The highest alphanumeric record


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.lumi-ai.com/product-features/knowledge-base/tables/preview-and-metametrics.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.