> ## Documentation Index
> Fetch the complete documentation index at: https://algolia.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Precision of custom ranking metrics

> Improve your custom ranking by reducing granularity, so that similar records are ranked equally.

When you rank records with business metrics, you want to make sure the difference between those values is significant.
Sometimes, the difference is too small to be taken into account.
Yet, when the engine performs tie-breaking between two records,
it doesn't make a difference whether you have 1,000 or 1,003 more views on a blog article.
If one has more than the other, it goes first.
Therefore, **you want to make sure that the values you use for custom ranking are properly weighted to avoid false positives**.

To fix that issue, what you can do is **reduce precision**.
An example is when you have blog articles,
ranked per different attributes like unique page views and number of comments.
You may have two posts with a close number of unique page views (1,000 and 1,003).
Therefore, you don't want the engine to break the tie on this attribute.
Instead, you want to move on to the next criteria to get better tie-breaking and more relevant results.

To run the code examples on this page, [install the latest API client](/doc/libraries/sdk/install).

## Modifying the data: an example

### Before

In this example, you're adding search to a blog.
Besides Algolia's default ranking formula,
you've set two custom ranking attributes: `pageviews` first, followed by `comments`.
Here's what the dataset would look like:

```json JSON icon=braces theme={"system"}
[
  {
    "title": "Algolia + SeaUrchin.IO",
    "author": "Nicolas Dessaigne",
    "pageviews": 1023,
    "comments": 23
  },
  {
    "title": "Search Analytics: Gain Insights from User Search Data",
    "author": "Nicolas Baissas",
    "pageviews": 508,
    "comments": 42
  },
  {
    "title": "Algolia Vault – Bringing Physical & Digital Data Security to Search",
    "author": "Liam Boogar",
    "pageviews": 1022,
    "comments": 54
  }
]
```

And here's the setting:

<CodeGroup>
  ```cs C# theme={"system"}
  var response = await client.SetSettingsAsync(
    "INDEX_NAME",
    new IndexSettings
    {
      CustomRanking = new List<string> { "desc(pageviews)", "desc(comments)" },
    }
  );
  ```

  ```dart Dart theme={"system"}
  final response = await client.setSettings(
    indexName: "INDEX_NAME",
    indexSettings: IndexSettings(
      customRanking: [
        "desc(pageviews)",
        "desc(comments)",
      ],
    ),
  );
  ```

  ```go Go theme={"system"}
  response, err := client.SetSettings(client.NewApiSetSettingsRequest(
    "INDEX_NAME",
    search.NewEmptyIndexSettings().SetCustomRanking(
      []string{"desc(pageviews)", "desc(comments)"})))
  if err != nil {
    // handle the eventual error
    panic(err)
  }
  ```

  ```java Java theme={"system"}
  UpdatedAtResponse response = client.setSettings(
    "INDEX_NAME",
    new IndexSettings().setCustomRanking(Arrays.asList("desc(pageviews)", "desc(comments)"))
  );
  ```

  ```js JavaScript theme={"system"}
  const response = await client.setSettings({
    indexName: 'theIndexName',
    indexSettings: { customRanking: ['desc(pageviews)', 'desc(comments)'] },
  });
  ```

  ```kotlin Kotlin theme={"system"}
  var response =
    client.setSettings(
      indexName = "INDEX_NAME",
      indexSettings = IndexSettings(customRanking = listOf("desc(pageviews)", "desc(comments)")),
    )
  ```

  ```php PHP theme={"system"}
  $response = $client->setSettings(
      'INDEX_NAME',
      ['customRanking' => [
          'desc(pageviews)',

          'desc(comments)',
      ],
      ],
  );
  ```

  ```python Python theme={"system"}
  response = client.set_settings(
      index_name="INDEX_NAME",
      index_settings={
          "customRanking": [
              "desc(pageviews)",
              "desc(comments)",
          ],
      },
  )
  ```

  ```ruby Ruby theme={"system"}
  response = client.set_settings(
    "INDEX_NAME",
    Algolia::Search::IndexSettings.new(custom_ranking: ["desc(pageviews)", "desc(comments)"])
  )
  ```

  ```scala Scala theme={"system"}
  val response = Await.result(
    client.setSettings(
      indexName = "INDEX_NAME",
      indexSettings = IndexSettings(
        customRanking = Some(Seq("desc(pageviews)", "desc(comments)"))
      )
    ),
    Duration(100, "sec")
  )
  ```

  ```swift Swift theme={"system"}
  let response = try await client.setSettings(
      indexName: "INDEX_NAME",
      indexSettings: IndexSettings(customRanking: ["desc(pageviews)", "desc(comments)"])
  )
  ```
</CodeGroup>

Because [custom ranking](/doc/guides/managing-results/must-do/custom-ranking) applies its criteria sequentially,
`pageviews` has more weight than `comments`.
When you search for "Algolia", the "Algolia + SeaUrchin IO" article comes before "Algolia Vault" only because it has one more unique page view. However, this additional view isn't meaningful. It doesn't make the article more relevant. Nonetheless, the engine ignores the next custom ranking attribute because of it.

For these two records, it would be better if the article with the most comments appeared first:
namely, that "Algolia Vault" article should come first because it has significantly more comments.

But changing the order of the attributes in the [`customRanking`](/doc/api-reference/api-parameters/customRanking) parameter isn't a good solution:

* It doesn't necessarily make sense business-wise (in this example, unique page views matter more than the number of comments),
* You may face the same issue with the number of comments, so this doesn't solve anything.

That's why you should **reduce precision to effectively use tie-breaking.**

### After

You can solve the issue by adding a `rounded_pageviews` attribute where you reduce the precision of `pageviews`,
and use it for custom ranking instead. For example, round page views to the nearest hundred.

```json JSON icon=braces theme={"system"}
[
  {
    "title": "Algolia + SeaUrchin.IO",
    "author": "Nicolas Dessaigne",
    "pageviews": 1023,
    "rounded_pageviews": 1000,
    "comments": 23
  },
  {
    "title": "Search Analytics: Gain Insights from User Search Data",
    "author": "Nicolas Baissas",
    "pageviews": 508,
    "rounded_pageviews": 500,
    "comments": 42
  },
  {
    "title": "Algolia Vault – Bringing Physical & Digital Data Security to Search",
    "author": "Liam Boogar",
    "pageviews": 1022,
    "rounded_pageviews": 1000,
    "comments": 54
  }
]
```

Then, you would use the `rounded_pageviews` attribute for custom ranking instead of `pageviews`.
Now, searching for "Algolia" would return the "Algolia Vault" article first, based on the `comments` attribute.

<CodeGroup>
  ```cs C# theme={"system"}
  var response = await client.SetSettingsAsync(
    "INDEX_NAME",
    new IndexSettings
    {
      CustomRanking = new List<string> { "desc(rounded_pageviews)", "desc(comments)" },
    }
  );
  ```

  ```dart Dart theme={"system"}
  final response = await client.setSettings(
    indexName: "INDEX_NAME",
    indexSettings: IndexSettings(
      customRanking: [
        "desc(rounded_pageviews)",
        "desc(comments)",
      ],
    ),
  );
  ```

  ```go Go theme={"system"}
  response, err := client.SetSettings(client.NewApiSetSettingsRequest(
    "INDEX_NAME",
    search.NewEmptyIndexSettings().SetCustomRanking(
      []string{"desc(rounded_pageviews)", "desc(comments)"})))
  if err != nil {
    // handle the eventual error
    panic(err)
  }
  ```

  ```java Java theme={"system"}
  UpdatedAtResponse response = client.setSettings(
    "INDEX_NAME",
    new IndexSettings().setCustomRanking(Arrays.asList("desc(rounded_pageviews)", "desc(comments)"))
  );
  ```

  ```js JavaScript theme={"system"}
  const response = await client.setSettings({
    indexName: 'theIndexName',
    indexSettings: { customRanking: ['desc(rounded_pageviews)', 'desc(comments)'] },
  });
  ```

  ```kotlin Kotlin theme={"system"}
  var response =
    client.setSettings(
      indexName = "INDEX_NAME",
      indexSettings =
        IndexSettings(customRanking = listOf("desc(rounded_pageviews)", "desc(comments)")),
    )
  ```

  ```php PHP theme={"system"}
  $response = $client->setSettings(
      'INDEX_NAME',
      ['customRanking' => [
          'desc(rounded_pageviews)',

          'desc(comments)',
      ],
      ],
  );
  ```

  ```python Python theme={"system"}
  response = client.set_settings(
      index_name="INDEX_NAME",
      index_settings={
          "customRanking": [
              "desc(rounded_pageviews)",
              "desc(comments)",
          ],
      },
  )
  ```

  ```ruby Ruby theme={"system"}
  response = client.set_settings(
    "INDEX_NAME",
    Algolia::Search::IndexSettings.new(custom_ranking: ["desc(rounded_pageviews)", "desc(comments)"])
  )
  ```

  ```scala Scala theme={"system"}
  val response = Await.result(
    client.setSettings(
      indexName = "INDEX_NAME",
      indexSettings = IndexSettings(
        customRanking = Some(Seq("desc(rounded_pageviews)", "desc(comments)"))
      )
    ),
    Duration(100, "sec")
  )
  ```

  ```swift Swift theme={"system"}
  let response = try await client.setSettings(
      indexName: "INDEX_NAME",
      indexSettings: IndexSettings(customRanking: ["desc(rounded_pageviews)", "desc(comments)"])
  )
  ```
</CodeGroup>

Note that this doesn't remove `pageviews` from the dataset.
You may want to keep it for display purposes.

To know more on how to rank per custom attributes, see the [guide](/doc/guides/managing-results/must-do/custom-ranking/how-to/configure-custom-ranking).