---
metadata:
  - name: generator
    content: Diplodoc Platform v5.52.0
alternate:
  - https://catboost.ai/docs/en/concepts/output-data_loss-function.md
  - href: en/concepts/output-data_loss-function.md
    type: text/markdown
    title: Markdown version
  - href: ../llms.txt
    type: text/markdown
    title: llms.txt
---
> **Documentation Index:** Fetch the complete configuration index at https://catboost.ai/docs/en/llms.txt

# Metric

#### Contains

<!-- source: en/_includes/work_src/reusage-formats/format__contains__metrics.md -->
The [metric](https://catboost.ai/docs/en/concepts/loss-functions.md) values for the training and test sets.

The table below lists the names of parameters that define the metric values to output. The values of all functions defined by these parameters are output.

Command-line version parameters| Python parameters | R parameters
-------------------------------|-------------------|------------------|
`--custom-metric`              | `custom_metric`   |  `custom_loss`   |
`--loss-function`              | `loss-function`   |  `loss-function` |
`--eval-metric`                | `eval-metric`     |  `eval-metric`   |
<!-- endsource: en/_includes/work_src/reusage-formats/format__contains__metrics.md -->


#### Format

- The first row describes the data provided in the file.

    Format:

    ```
    iter<\t><loss 1><loss 2><\t>...<\t><loss N>
    ```

- The metric names are expanded by colon-separated numbers if several validation datasets are input. The numbers correspond to the serial number of the input dataset.
- All the rows except the first contain information for the specific iteration of building the tree.

    Format:

    ```
    <tree index><\t><loss 1><loss 2><\t>...<\t><loss N>
    ```


#### Examples

```
iter<\t>Logloss<\t>AUC
0<\t>0.6637258841<\t>0.8800403474
1<\t>0.6358649829<\t>0.8898645092
2<\t>0.6118586328<\t>0.8905880184
3<\t>0.5882755767<\t>0.8911104564
4<\t>0.5665035887<\t>0.8933460724
```

The output for three input validation datasets:
```
iter<\t>RMSE<\t>RMSE:1<\t>RMSE:2
0<\t>0.114824346<\t>0.1105841934<\t>0.08683344953
1<\t>0.1136556268<\t>0.1095536596<\t>0.08584400666
2<\t>0.1125784149<\t>0.10852689<\t>0.08494974738
3<\t>0.1114784956<\t>0.1075251632<\t>0.08401943147
4<\t>0.1103751142<\t>0.106557555<\t>0.08312388916
```