info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/product/ux/technical-writing/#assignments
| `id` | integer/string | yes | The ID or [URL-encoded path of the project](../index.md#namespaced-path-encoding) can be accessed by the authenticated user. |
| `metric` | string | yes | One of `deployment_frequency`, `lead_time_for_changes`, `time_to_restore_service` or `change_failure_rate`. |
| `end_date` | string | no | Date range to end at. ISO 8601 Date format, for example `2021-03-01`. Default is the current date. |
| `environment_tier` | string | no | The [tier of the environment](../../ci/environments/index.md#deployment-tier-of-environments). Default is `production`. Deprecated, please 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](../index.md#namespaced-path-encoding) can be accessed by the authenticated user. |
| `metric` | string | yes | One of `deployment_frequency`, `lead_time_for_changes`, `time_to_restore_service` or `change_failure_rate`. |
| `end_date` | string | no | Date range to end at. ISO 8601 Date format, for example `2021-03-01`. Default is the current date. |
| `environment_tier` | string | no | The [tier of the environment](../../ci/environments/index.md#deployment-tier-of-environments). Default is `production`. Deprecated, please 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. |
| `change_failure_rate` | The number of incidents divided by the number of deployments during the time period. Available only for production environment. |
| `deployment_frequency` | The number of successful deployments during the time period. |
| `lead_time_for_changes` | The median number of seconds between the merge of the merge request (MR) and the deployment of the MR's commits for all MRs deployed during the time period. |
| `time_to_restore_service` | The median number of seconds an incident was open during the time period. Available only for production environment. |
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.