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| `id` | integer/string | yes | The ID or [URL-encoded path of the project](../rest/index.md#namespaced-path-encoding) can be accessed by the authenticated user. |
| `environment_tier` | string | no | The [tier of the environment](../../ci/environments/index.md#deployment-tier-of-environments). Default is `production`. Deprecated, use `environment_tiers`. |
| `environment_tiers` | array of strings | no | The [tiers of the environments](../../ci/environments/index.md#deployment-tier-of-environments). Default is `production`. |
| `interval` | string | no | The bucketing interval. One of `all`, `monthly` or `daily`. Default is `daily`. |
| `start_date` | string | no | Date range to start from. ISO 8601 Date format, for example `2021-03-01`. Default is 3 months ago. |
| `id` | integer/string | yes | The ID or [URL-encoded path of the project](../rest/index.md#namespaced-path-encoding) can be accessed by the authenticated user. |
| `environment_tier` | string | no | The [tier of the environment](../../ci/environments/index.md#deployment-tier-of-environments). Default is `production`. Deprecated, use `environment_tiers`. |
| `environment_tiers` | array of strings | no | The [tiers of the environments](../../ci/environments/index.md#deployment-tier-of-environments). Default is `production`. |
| `interval` | string | no | The bucketing interval. One of `all`, `monthly` or `daily`. Default is `daily`. |
| `start_date` | string | no | Date range to start from. ISO 8601 Date format, for example `2021-03-01`. Default is 3 months ago. |
| `deployment_frequency` | The API returns the total number of successful deployments during the time period. [Issue 371271](https://gitlab.com/gitlab-org/gitlab/-/issues/371271) proposes to update the API to return the daily average instead of the total number. |
| `change_failure_rate` | The number of incidents divided by the number of deployments during the time period. Available only for production environment. |
| `lead_time_for_changes` | The median number of seconds between the merge of the merge request (MR) and the deployment of the MR commits for all MRs deployed during the time period. |
The API returns the `monthly` and `all` intervals by calculating the median of the daily median values. This can introduce a slight inaccuracy in the returned data.